An Etymological Dictionary of Astronomy and Astrophysics

A large → H II region in the north part of → Orion’s Sword composed of reflection and emission components ( → reflection nebula, → emission nebula). It includes NGC 1977, NGC 1975, and NGC 1973, separated from each other by a → dark nebula which resembles a running man, as well as the → open cluster NGC 1981. NGC 1977, the designation some sources use to describe the entire complex, is the largest and brightest nebulous component first described by Herschel in 1786. The nebula is approximately 40 arcmin in apparent diameter, and 1,500 → light-years distant.

See also: Nebula number 279 in the second edition of the → Sharpless catalog.

A large → H II region in the north part of → Orion’s Sword composed of reflection and emission components ( → reflection nebula, → emission nebula). It includes NGC 1977, NGC 1975, and NGC 1973, separated from each other by a → dark nebula which resembles a running man, as well as the → open cluster NGC 1981. NGC 1977, the designation some sources use to describe the entire complex, is the largest and brightest nebulous component first described by Herschel in 1786. The nebula is approximately 40 arcmin in apparent diameter, and 1,500 → light-years distant.

See also: Nebula number 279 in the second edition of the → Sharpless catalog.

An optical device, a modern version of the → Hartmann test, used for analyzing the wavefront of light. Theses sensors can be used to characterize the performance of optical systems. Moreover, they are increasingly used in real-time applications, such as
→ adaptive optics to remove the wavefront distortion before creating an image. It consists of a microlens array placed in front of a CCD array. A planar wavefront that is transmitted through a microlens array and imaged on the CCD array will form a regular pattern of bright spots. If, however, the wavefront is distorted, the light imaged on the CCD will consist of some regularly spaced spots mixed with displaced spots and missing spots. This information is used to calculate the shape of the wavefront that was incident on the microlens array.

See also: Named after the German astronomer Johannes Hartmann (1865-1936), who first developed the method, and R. V. Shack, who in the late 1960s replaced the
screen by a microlens array; → wavefront; → sensor.

An optical device, a modern version of the → Hartmann test, used for analyzing the wavefront of light. Theses sensors can be used to characterize the performance of optical systems. Moreover, they are increasingly used in real-time applications, such as
→ adaptive optics to remove the wavefront distortion before creating an image. It consists of a microlens array placed in front of a CCD array. A planar wavefront that is transmitted through a microlens array and imaged on the CCD array will form a regular pattern of bright spots. If, however, the wavefront is distorted, the light imaged on the CCD will consist of some regularly spaced spots mixed with displaced spots and missing spots. This information is used to calculate the shape of the wavefront that was incident on the microlens array.

See also: Named after the German astronomer Johannes Hartmann (1865-1936), who first developed the method, and R. V. Shack, who in the late 1960s replaced the
screen by a microlens array; → wavefront; → sensor.

1. The comparative darkness caused by the interception or screening of rays of light from an object, place, or area.
   

2. A place or an area of comparative darkness, as one sheltered from the sun (Dictionary.com). See also → shadow.

Etymology (EN): M.E. schade; O.E. scead “partial darkness; shelter,” → shadow.

Etymology (PE): Sivân, from Kurd. sayvân “shadow, shade,” variants si, sâ, sâyé, → shadow.

1. The comparative darkness caused by the interception or screening of rays of light from an object, place, or area.
   

2. A place or an area of comparative darkness, as one sheltered from the sun (Dictionary.com). See also → shadow.

Etymology (EN): M.E. schade; O.E. scead “partial darkness; shelter,” → shadow.

Etymology (PE): Sivân, from Kurd. sayvân “shadow, shade,” variants si, sâ, sâyé, → shadow.

A dark patch formed by a body which obstructs rays of light.

Etymology (EN): M.E. sch(e)adew(e), schadow, shadw(e),
O.E. sceadwe, sceaduwe, sceadu “shade, shadow, darkness;” cf. O.S. skado, M.Du. scade, Du. schaduw, O.H.G. scato, Ger. Schatten, Goth. skadus; from PIE base *skot- “dark, shade.”

Etymology (PE): Sâyé “shadow,” from Mid.Pers. sâyak “shadow;” Av. a-saya- “throwing no shadow;” Skt. chāya- “shadow;” Gk. skia “shade;” Rus. sijat’ “to shine;”
M.H.G. schinen, O.H.G. skinan, Ger. Schein “glow, shine;” PIE base *skai- “bright.”

A dark patch formed by a body which obstructs rays of light.

Etymology (EN): M.E. sch(e)adew(e), schadow, shadw(e),
O.E. sceadwe, sceaduwe, sceadu “shade, shadow, darkness;” cf. O.S. skado, M.Du. scade, Du. schaduw, O.H.G. scato, Ger. Schatten, Goth. skadus; from PIE base *skot- “dark, shade.”

Etymology (PE): Sâyé “shadow,” from Mid.Pers. sâyak “shadow;” Av. a-saya- “throwing no shadow;” Skt. chāya- “shadow;” Gk. skia “shade;” Rus. sijat’ “to shine;”
M.H.G. schinen, O.H.G. skinan, Ger. Schein “glow, shine;” PIE base *skai- “bright.”

Faint wavy lines of alternating light and dark that sometimes can be seen on flat, light-colored surfaces just before and just after a total solar eclipse. The phenomenon results from sunlight distortion by irregularities in the Earth’s atmosphere.

See also: → shadow; → band.

Faint wavy lines of alternating light and dark that sometimes can be seen on flat, light-colored surfaces just before and just after a total solar eclipse. The phenomenon results from sunlight distortion by irregularities in the Earth’s atmosphere.

See also: → shadow; → band.

A cone-shaped shadow cast by Earth or the Moon pointing away from the Sun. The dark inner portion of the shadow cone is called the → umbra. The lighter outer portion of the shadow is called the → penumbra. Its extension is called the → antumbra.

See also: → shadow; → cone.

A cone-shaped shadow cast by Earth or the Moon pointing away from the Sun. The dark inner portion of the shadow cone is called the → umbra. The lighter outer portion of the shadow is called the → penumbra. Its extension is called the → antumbra.

See also: → shadow; → cone.

A fissile rock composed mostly of layers of clay-like, fine-grained → sediments. Shale is the most frequently occurring → sedimentary rock.

Etymology (EN): Probably from obsolete or dialect shale “scale, shell,” from M.E., from O.E. scealu, → rock.

Etymology (PE): Ardavâl “shale,” in the dialectal Mod.Pers. of Golpâyegân, Arâk, Xonsâr, etc.

A fissile rock composed mostly of layers of clay-like, fine-grained → sediments. Shale is the most frequently occurring → sedimentary rock.

Etymology (EN): Probably from obsolete or dialect shale “scale, shell,” from M.E., from O.E. scealu, → rock.

Etymology (PE): Ardavâl “shale,” in the dialectal Mod.Pers. of Golpâyegân, Arâk, Xonsâr, etc.

Of little depth; not deep.

Etymology (EN): M.E. schalowe, akin to O.E. sceald “shallow.”

Etymology (PE): Nažal, from negation prefix na-, → non-,

• žal “deep,” variant of jal, jol, jul, → deep.

Of little depth; not deep.

Etymology (EN): M.E. schalowe, akin to O.E. sceald “shallow.”

Etymology (PE): Nažal, from negation prefix na-, → non-,

• žal “deep,” variant of jal, jol, jul, → deep.

Low angle, → grazing incidence.

See also: → shallow; → angle.

Low angle, → grazing incidence.

See also: → shallow; → angle.

The part of the → leg between the → knee and the → ankle in humans.

Etymology (EN): O.E. sceanca “leg, shank, shinbone;” cf. Ger. schenkel “shank, leg,” Dan., Swed. skank “leg;” maybe somehow related to Pers. leng, → leg.

Etymology (PE): Sâq “the leg from the ankle to the knee; the stem of a tree,” maybe a variant of šâx “a branch, bough; a horn,” or loan from Ar.

The part of the → leg between the → knee and the → ankle in humans.

Etymology (EN): O.E. sceanca “leg, shank, shinbone;” cf. Ger. schenkel “shank, leg,” Dan., Swed. skank “leg;” maybe somehow related to Pers. leng, → leg.

Etymology (PE): Sâq “the leg from the ankle to the knee; the stem of a tree,” maybe a variant of šâx “a branch, bough; a horn,” or loan from Ar.

→ information entropy.

See also: Claude Elwood Shannon (1916-2001), an American mathematician and pioneer of → information theory; → entropy.

→ information entropy.

See also: Claude Elwood Shannon (1916-2001), an American mathematician and pioneer of → information theory; → entropy.

Same as → sampling theorem.

See also: → Shannon entropy; → sampling; → theorem.

Same as → sampling theorem.

See also: → Shannon entropy; → sampling; → theorem.

The appearance of something in terms of its arrangement in space, especially its outline.

Etymology (EN): M.E., from O.E. sceapen, gescapen, p.p. of scieppan; cognate with O.H.G. skepfen “to shape.”

Etymology (PE): Šekl, → figure; dise, → form.

The appearance of something in terms of its arrangement in space, especially its outline.

Etymology (EN): M.E., from O.E. sceapen, gescapen, p.p. of scieppan; cognate with O.H.G. skepfen “to shape.”

Etymology (PE): Šekl, → figure; dise, → form.

A → general relativity effect whereby an → electromagnetic signal passing near a massive object takes, due to the curved → space-time,
a slightly longer time to travel to a target than it would if the mass of the object were not present. The Shapiro time delay is one of the four classic solar system tests of general relativity. Radar reflections from → Mercury and → Mars are consistent with general relativity to an accuracy of about 5%. The Shapiro time delay is a significant contributor in → gravitational lens systems.

See also: Irwin I. Shapiro, an American astrophysicist; → time; → delay.

A → general relativity effect whereby an → electromagnetic signal passing near a massive object takes, due to the curved → space-time,
a slightly longer time to travel to a target than it would if the mass of the object were not present. The Shapiro time delay is one of the four classic solar system tests of general relativity. Radar reflections from → Mercury and → Mars are consistent with general relativity to an accuracy of about 5%. The Shapiro time delay is a significant contributor in → gravitational lens systems.

See also: Irwin I. Shapiro, an American astrophysicist; → time; → delay.

Same as the → Shapley supercluster.

See also: → Shapley’s wing; → concentration

Same as the → Shapley supercluster.

See also: → Shapley’s wing; → concentration

The richest → supercluster of galaxies in the nearby → Universe at a → redshift going from z ~0.03 to z ~0.05 (680 million → light-years), and extending over several square degrees on the plane of the sky. It lies behind the
→ Centaurus supercluster. Also called the Shapley concentration, it is made up of 25 → galaxy clusters with a total mass of about 10¹⁶→ solar masses. At the core of the Shapley supercluster is a remarkable complex formed by several rich clusters of galaxies from the → Abell catalog; the central and most massive of them is
A3558.

See also: → Shapley’s wing; → supercluster

The richest → supercluster of galaxies in the nearby → Universe at a → redshift going from z ~0.03 to z ~0.05 (680 million → light-years), and extending over several square degrees on the plane of the sky. It lies behind the
→ Centaurus supercluster. Also called the Shapley concentration, it is made up of 25 → galaxy clusters with a total mass of about 10¹⁶→ solar masses. At the core of the Shapley supercluster is a remarkable complex formed by several rich clusters of galaxies from the → Abell catalog; the central and most massive of them is
A3558.

See also: → Shapley’s wing; → supercluster

A catalog of 1,249 galaxies, brighter than the 13th magnitude, published in 1932. A revised version was published by A.R. Sandage and G. A. Tammann in 1981.

See also: By the American astronomer Harlow Shapley (1885-1972) and the American woman astronomer Adelaide Ames (1900-1932), who died in a drowning accident; → catalog.

A catalog of 1,249 galaxies, brighter than the 13th magnitude, published in 1932. A revised version was published by A.R. Sandage and G. A. Tammann in 1981.

See also: By the American astronomer Harlow Shapley (1885-1972) and the American woman astronomer Adelaide Ames (1900-1932), who died in a drowning accident; → catalog.

A large cloud of faint stars extending eastward from the → Small Magellanic Cloud to the → Large Magellanic Cloud. The wing is in fact the tail of a much larger → neutral hydrogen structure linking the SMC to the LMC. Models and observations suggest that the structure known as the → Magellanic Stream results from the Clouds’ interaction with each other and the Milky Way. Several works support the finding that the SMC wing is pointing toward the LMC, and is therefore closer to us than the SMC bar.

See also: Named after the American astronomer Harlow Shapley (1885-1972), who discovered this structure (1940, Harvard Bull., 914, 8); → wing.

A large cloud of faint stars extending eastward from the → Small Magellanic Cloud to the → Large Magellanic Cloud. The wing is in fact the tail of a much larger → neutral hydrogen structure linking the SMC to the LMC. Models and observations suggest that the structure known as the → Magellanic Stream results from the Clouds’ interaction with each other and the Milky Way. Several works support the finding that the SMC wing is pointing toward the LMC, and is therefore closer to us than the SMC bar.

See also: Named after the American astronomer Harlow Shapley (1885-1972), who discovered this structure (1940, Harvard Bull., 914, 8); → wing.

→ linear astrolabe.

See also: Named after the Iranian mathematician and astronomer Sharafeddin Tusi (c1135-1213), who invented the instrument. Not to be confused with Nasireddin Tusi (1201-1274), → Nasireddin couple; → staff.

→ linear astrolabe.

See also: Named after the Iranian mathematician and astronomer Sharafeddin Tusi (c1135-1213), who invented the instrument. Not to be confused with Nasireddin Tusi (1201-1274), → Nasireddin couple; → staff.

1a) The full or proper portion or part allotted or belonging to or contributed or owed by an individual or group.

1b) One of the equal fractional parts into which the capital stock of a joint-stock company or a corporation is divided.

2a) To divide and distribute in shares; apportion.

2b) To use, participate in, enjoy, receive, etc., jointly (Dictionary.com).

Etymology (EN): M.E., from O.E. scearu “a cutting, shearing; a part or division,” related to sceran “to cut;” O.H.G. scara “troop, share of forced labor,” Ger. Schar “troop, band,” properly “a part of an army,” O.N. skör “rim;” from PIE root *(s)ker- “to cut.”

Etymology (PE): Bâš, from Kurd. (Sorani) baš “share, part;” variant of baxš “share, portion;” baxšidan “to divide,” → division; bâž “tribute, toll, impost,” → distribute.

1a) The full or proper portion or part allotted or belonging to or contributed or owed by an individual or group.

1b) One of the equal fractional parts into which the capital stock of a joint-stock company or a corporation is divided.

2a) To divide and distribute in shares; apportion.

2b) To use, participate in, enjoy, receive, etc., jointly (Dictionary.com).

Etymology (EN): M.E., from O.E. scearu “a cutting, shearing; a part or division,” related to sceran “to cut;” O.H.G. scara “troop, share of forced labor,” Ger. Schar “troop, band,” properly “a part of an army,” O.N. skör “rim;” from PIE root *(s)ker- “to cut.”

Etymology (PE): Bâš, from Kurd. (Sorani) baš “share, part;” variant of baxš “share, portion;” baxšidan “to divide,” → division; bâž “tribute, toll, impost,” → distribute.

1. Having a thin cutting edge or a fine point.
   

2. Of an image, clearly defined; distinct. → sharp image.

Etymology (EN): M.E.; O.E. scearp “cutting, keen, sharp;” cf. Du. scherp, Ger. scharf “sharp;” PIE base *(s)ker- “to cut.”

Etymology (PE): Tiz “sharp,” variants tež, tej, tij, tiq, tik, tig;
Mid.Pers. tigr, têz, têž “sharp;” O.Pers. tigra- “pointed,”
tigra.xauda- “pointed helmet (epithet of Scythians);” Av. tiγra- “pointed,” tiγray- “arrow,” tiži.arštay- “with the pointed spear;” cf. Skt. tikta- “sharp, pungent, bitter,” tejas- “sharpness, edge, point or top of a flame;” PIE base *st(e)ig- “to stick; pointed.” Cognates in other IE languages: Gk. stizein “to prick, puncture,” stigma “mark made by a pointed instrument;” L. in-stigare “to goad;” O.H.G. stehhan; Ger. stechen “to stab, prick;” Du. stecken;
O.E. sticca “rod, twig, spoon;” E. stick.

1. Having a thin cutting edge or a fine point.
   

2. Of an image, clearly defined; distinct. → sharp image.

Etymology (EN): M.E.; O.E. scearp “cutting, keen, sharp;” cf. Du. scherp, Ger. scharf “sharp;” PIE base *(s)ker- “to cut.”

Etymology (PE): Tiz “sharp,” variants tež, tej, tij, tiq, tik, tig;
Mid.Pers. tigr, têz, têž “sharp;” O.Pers. tigra- “pointed,”
tigra.xauda- “pointed helmet (epithet of Scythians);” Av. tiγra- “pointed,” tiγray- “arrow,” tiži.arštay- “with the pointed spear;” cf. Skt. tikta- “sharp, pungent, bitter,” tejas- “sharpness, edge, point or top of a flame;” PIE base *st(e)ig- “to stick; pointed.” Cognates in other IE languages: Gk. stizein “to prick, puncture,” stigma “mark made by a pointed instrument;” L. in-stigare “to goad;” O.H.G. stehhan; Ger. stechen “to stab, prick;” Du. stecken;
O.E. sticca “rod, twig, spoon;” E. stick.

An image with clear and distinct details. Opposite of → blurred image.

See also: → sharp; → image.

An image with clear and distinct details. Opposite of → blurred image.

See also: → sharp; → image.

1. To make sharp or sharper.
   
2. To increase the spatial resolution or the clearness of an image; same as → deblur; → deconvolve.

Etymology (EN): Verbal form of → sharp.

Etymology (PE): Tigidan “to sharpen,” verbal form of tig→ sharp.

1. To make sharp or sharper.
   
2. To increase the spatial resolution or the clearness of an image; same as → deblur; → deconvolve.

Etymology (EN): Verbal form of → sharp.

Etymology (PE): Tigidan “to sharpen,” verbal form of tig→ sharp.

A list of 313 individual → H II regions in the → northern → Milky Way (north of declination -27°). It includes several → planetary nebulae, → supernova remnants, and → reflection nebulae. The first edition (Sh-1) was published in 1953 with 142 objects and second and final version (Sh-2) was published in 1959. The catalog categorizes the H II regions in terms of several parameters, such as diameter, form (circular, elliptical, irregular), structure (amorphous/filamentary), brightness, and number of associated stars, which are further discussed in terms of their spectral classes.

See also: Stewart Sharpless (1959) A Catalogue of H II Regions, ApJ Suppl. 4, 257; → catalog.

A list of 313 individual → H II regions in the → northern → Milky Way (north of declination -27°). It includes several → planetary nebulae, → supernova remnants, and → reflection nebulae. The first edition (Sh-1) was published in 1953 with 142 objects and second and final version (Sh-2) was published in 1959. The catalog categorizes the H II regions in terms of several parameters, such as diameter, form (circular, elliptical, irregular), structure (amorphous/filamentary), brightness, and number of associated stars, which are further discussed in terms of their spectral classes.

See also: Stewart Sharpless (1959) A Catalogue of H II Regions, ApJ Suppl. 4, 257; → catalog.

The second brightest star in the constellation → Scorpius, lying at a distance of 570 → light-years. With → Lesath (Upsilon Scorpii) both stars make up the Scorpion’s stinger. Shaula is a → multiple star with three visible → components. The first one, Lambda Scorpii A, is classified as a B2 IV → subgiant. The 15th magnitude Lambda Scorpii B has a separation of 42 arcseconds from component A, while the 12th magnitude Lambda Scorpii C is 95 arcseconds from A. It is not known whether or not these components are physically associated with component A. The component A is actually a → triple system consisting of two → B-type stars and a → pre-main sequence star.

See also: Shaula, from Ar. ash-shaulah (الشولاء) the “raised tail” of Scorpion.

The second brightest star in the constellation → Scorpius, lying at a distance of 570 → light-years. With → Lesath (Upsilon Scorpii) both stars make up the Scorpion’s stinger. Shaula is a → multiple star with three visible → components. The first one, Lambda Scorpii A, is classified as a B2 IV → subgiant. The 15th magnitude Lambda Scorpii B has a separation of 42 arcseconds from component A, while the 12th magnitude Lambda Scorpii C is 95 arcseconds from A. It is not known whether or not these components are physically associated with component A. The component A is actually a → triple system consisting of two → B-type stars and a → pre-main sequence star.

See also: Shaula, from Ar. ash-shaulah (الشولاء) the “raised tail” of Scorpion.

Same as → supra-horizontal branch star.

See also: → supra-; → horizontal; → branch; → star.

Same as → supra-horizontal branch star.

See also: → supra-; → horizontal; → branch; → star.

1. (n.) General: A scissors of large size.
   Physics: A → stress applied to a body in the plane of its faces or perpendicular to its axis. As a consequence, parallel planes in the body remain parallel, but are displaced in a direction parallel to themselves. See also → strain.
   

2. (v.) General: To cut hair, fleece, or foliage from the surface of something using a sharp tool.
   Physics: To cause something to deform or break by applying forces acting parallel to the plane.

Etymology (EN): M.E. sheren, O.E. sceran, scieran;
cf. O.H.G. scrinden “to split;”, Du. scheren, Ger. scheren “to shear;” from PIE *(s)ker- “to cut, to scrape, to hack;” cf. Pers. kârd “knife;” Av. kart- “to cut;” Skt. krntáti “cuts;” Gk. keirein “to cut, shear;” Lith. skiriu “to separate.”

Etymology (PE): 1) Karn, from Laki caré, Farâhâni carra, Tabari carci “a scissors for cutting sheep wool,” cognate with Pers. kârd “knife; " Mid.Pers. kârt “knife,” karēnītan, karītan “to cut;” Av. karət- “to cut;” cf. Skt. kart- “to cut,” krpāna- “sword, knife;”
Gk. karpos “fruit;” L. carpere “to cut, divide, pluck;” PIE base *(s)ker- “to cut.”
Karnidan infinitive from karn.

1. (n.) General: A scissors of large size.
   Physics: A → stress applied to a body in the plane of its faces or perpendicular to its axis. As a consequence, parallel planes in the body remain parallel, but are displaced in a direction parallel to themselves. See also → strain.
   

2. (v.) General: To cut hair, fleece, or foliage from the surface of something using a sharp tool.
   Physics: To cause something to deform or break by applying forces acting parallel to the plane.

Etymology (EN): M.E. sheren, O.E. sceran, scieran;
cf. O.H.G. scrinden “to split;”, Du. scheren, Ger. scheren “to shear;” from PIE *(s)ker- “to cut, to scrape, to hack;” cf. Pers. kârd “knife;” Av. kart- “to cut;” Skt. krntáti “cuts;” Gk. keirein “to cut, shear;” Lith. skiriu “to separate.”

Etymology (PE): 1) Karn, from Laki caré, Farâhâni carra, Tabari carci “a scissors for cutting sheep wool,” cognate with Pers. kârd “knife; " Mid.Pers. kârt “knife,” karēnītan, karītan “to cut;” Av. karət- “to cut;” cf. Skt. kart- “to cut,” krpāna- “sword, knife;”
Gk. karpos “fruit;” L. carpere “to cut, divide, pluck;” PIE base *(s)ker- “to cut.”
Karnidan infinitive from karn.

The ratio of the applied → stress to the change in shape (→ strain) produced in an → elastic body. The bigger this quantity the more rigid is the material since for the same change in strain
a bigger force is needed. Also called → shear modulus.

See also: → shear; → modulus.

The ratio of the applied → stress to the change in shape (→ strain) produced in an → elastic body. The bigger this quantity the more rigid is the material since for the same change in strain
a bigger force is needed. Also called → shear modulus.

See also: → shear; → modulus.

A type of → instability occurring within a → fluid as a result of the → shear caused by → differential rotation.
The condition for shear instability is expressed by the → Richardson criterion. Shear turbulence is likely the most efficient → mixing process in stellar
→ radiative zones.

See also: → shear; → turbulence.

A type of → instability occurring within a → fluid as a result of the → shear caused by → differential rotation.
The condition for shear instability is expressed by the → Richardson criterion. Shear turbulence is likely the most efficient → mixing process in stellar
→ radiative zones.

See also: → shear; → turbulence.

A wave that occurs in an elastic medium with the disturbances perpendicular to the direction of motion of the wave. Shear waves do not propagate through a fluid. Also called S-wave, secondary wave, and transverse wave.

See also: → shear; → wave.

A wave that occurs in an elastic medium with the disturbances perpendicular to the direction of motion of the wave. Shear waves do not propagate through a fluid. Also called S-wave, secondary wave, and transverse wave.

See also: → shear; → wave.

The brightest star in the constellation → Cassiopeia. It is a supergiant K0 III star with a visual magnitude of 2.23 at a distance of 230 light-years. It has a large luminosity, 855 times that of our Sun, and a notable size, 48 times that of the Sun. Its effective temperature is 4530 K. Name variants: Schedar, Shedar, and Schedir. Also known as HR 168 and HD 3712.

See also: From Ar. as-sadr (الصدر) “chest, breast,” contraction of as-sadr-al-Zat-al-kursi (الصدر‌الذات‌الکرسی) “the chest of the throne’s owner” or “the chest of the seated one” referring to the Ar. rendering of the character in Gk. mythology.

The brightest star in the constellation → Cassiopeia. It is a supergiant K0 III star with a visual magnitude of 2.23 at a distance of 230 light-years. It has a large luminosity, 855 times that of our Sun, and a notable size, 48 times that of the Sun. Its effective temperature is 4530 K. Name variants: Schedar, Shedar, and Schedir. Also known as HR 168 and HD 3712.

See also: From Ar. as-sadr (الصدر) “chest, breast,” contraction of as-sadr-al-Zat-al-kursi (الصدر‌الذات‌الکرسی) “the chest of the throne’s owner” or “the chest of the seated one” referring to the Ar. rendering of the character in Gk. mythology.

A domesticated ruminant mammal with a thick woolly coat and (typically only in the male) curving horns. It is kept in flocks for its wool or meat (OxfordDictionaries.com).

Etymology (EN): M.E., from O.E. sceap; related to O.Frisian skep, O.Saxon scap, O.H.G. scaf, Ger. Schaf.

Etymology (PE): Gusfand, guspand, from Mid.Pers. gôspand “cattle in general,” especially “sheep, goats,” as distinguished from horses and cows, Av. gaospənta- “sanctified, consecrated cow,” from gao-, → cow,

• spənta- “sanctfied, holy,” → holiday.

A domesticated ruminant mammal with a thick woolly coat and (typically only in the male) curving horns. It is kept in flocks for its wool or meat (OxfordDictionaries.com).

Etymology (EN): M.E., from O.E. sceap; related to O.Frisian skep, O.Saxon scap, O.H.G. scaf, Ger. Schaf.

Etymology (PE): Gusfand, guspand, from Mid.Pers. gôspand “cattle in general,” especially “sheep, goats,” as distinguished from horses and cows, Av. gaospənta- “sanctified, consecrated cow,” from gao-, → cow,

• spənta- “sanctfied, holy,” → holiday.

1. General: A relatively thin external form covering a hollow space.
   

2. The hard exterior of an egg; a hard outer covering of an animal, such as a mollusk.
   

3. Physics: → electron shell.
   

4. → seashell.
   

5. Astro.: → shell burning; → shell galaxy; → shell star; → shellular rotation; → SNR shell.

Etymology (EN): M.E.; from O.E. scell, sciell; cognate with Dutch schil “peel, skin,” O.Norse skel “shell,” from PIE root *(s)ker “to cut,” → bark.

Etymology (PE): Pusté “shell,” from pust “skin;” Mid.Pers. pôst “skin;” O.Pers. pavastā- “thin clay envelope used to protect unbaked clay tablets;” Av. pastô-, in pastô.fraθanhəm “of the breadth of the skin;” Skt. pavásta- “cover,” Proto-Indo-Iranian pauastā- “cloth.”
Pukel, from (Nahâvand, Hamadân, Ilâm) pukel “egg shell,” (Kurd.) tukel, probably (prefixed) from PIE root (s)ker- “to cut,” → bark, → scalp.

1. General: A relatively thin external form covering a hollow space.
   

2. The hard exterior of an egg; a hard outer covering of an animal, such as a mollusk.
   

3. Physics: → electron shell.
   

4. → seashell.
   

5. Astro.: → shell burning; → shell galaxy; → shell star; → shellular rotation; → SNR shell.

Etymology (EN): M.E.; from O.E. scell, sciell; cognate with Dutch schil “peel, skin,” O.Norse skel “shell,” from PIE root *(s)ker “to cut,” → bark.

Etymology (PE): Pusté “shell,” from pust “skin;” Mid.Pers. pôst “skin;” O.Pers. pavastā- “thin clay envelope used to protect unbaked clay tablets;” Av. pastô-, in pastô.fraθanhəm “of the breadth of the skin;” Skt. pavásta- “cover,” Proto-Indo-Iranian pauastā- “cloth.”
Pukel, from (Nahâvand, Hamadân, Ilâm) pukel “egg shell,” (Kurd.) tukel, probably (prefixed) from PIE root (s)ker- “to cut,” → bark, → scalp.

The nuclear reactions in a shell around a star’s core that continue after the fuel in the core itself has been exhausted. As the fuel is progressively exhausted, the shell moves outward until it enters regions too cool for the reactions to continue. For example, after the exhaustion of hydrogen in the core, helium burning might take place in the core with a shell of hydrogen burning surrounding it. Stars may have more than one region of shell burning during their stellar evolution, each shell with its own nuclear reactions. → hydrogen shell burning; → helium shell burning.

See also: → shell; → burning.

The nuclear reactions in a shell around a star’s core that continue after the fuel in the core itself has been exhausted. As the fuel is progressively exhausted, the shell moves outward until it enters regions too cool for the reactions to continue. For example, after the exhaustion of hydrogen in the core, helium burning might take place in the core with a shell of hydrogen burning surrounding it. Stars may have more than one region of shell burning during their stellar evolution, each shell with its own nuclear reactions. → hydrogen shell burning; → helium shell burning.

See also: → shell; → burning.

An elliptical galaxy that is surrounded by thin shells of stars which are thought to have been ejected during a galaxy merger. Shell galaxies are different from ring galaxies in that the shells are much further away from the galaxy’s centre and much fainter than the rings. Spectroscopy of the stars in the shell show that they are old whereas the stars in a ring galaxy are young.

See also: → shell; → galaxy.

An elliptical galaxy that is surrounded by thin shells of stars which are thought to have been ejected during a galaxy merger. Shell galaxies are different from ring galaxies in that the shells are much further away from the galaxy’s centre and much fainter than the rings. Spectroscopy of the stars in the shell show that they are old whereas the stars in a ring galaxy are young.

See also: → shell; → galaxy.

A main-sequence star, usually of spectral class B to F, whose spectrum shows bright emission lines superimposed on the normal absorption lines. The emission spectrum is explained by the presence of a circumstellar shell of gas surrounding the star at the equator.
Shell stars are fast rotators.

See also: → shell; → star.

A main-sequence star, usually of spectral class B to F, whose spectrum shows bright emission lines superimposed on the normal absorption lines. The emission spectrum is explained by the presence of a circumstellar shell of gas surrounding the star at the equator.
Shell stars are fast rotators.

See also: → shell; → star.

A rotation mode in which internal rotation of a star depends essentially on
depth and little on latitude: Ω(r,θ) = Ω(r), where r is the mean distance to the stellar center of the considered level surface (or → isobar).
This particular mode was introduced by J.-P. Zahn (1992, A&A 265, 115) to simplify the treatment of rotational → mixing, but also on more physical grounds. Indeed differential rotation tends to be smoothed out in latitude through → shear turbulence. See also → von Zeipel theorem; → meridional circulation .

Etymology (EN): Shellular, the structure of this term is not clear; it may be a combination of → shell (referring to star’s assumed division in differentially rotating concentric shells) + (circ)ular, → circular. The first bibliographic occurrence of shellular is seemingly in Ghosal & Spiegel (1991, On the Thermonuclear Convection: I. Shellular Instability, Geophys. Astrophys. Fluid Dyn. 61, 161). However, surprisingly the term appears only in the title, and nowhere in the body of the article; → rotation.

Etymology (PE): Carxeš, → rotation; puste-yi, adj. of pusté, → shell.

A rotation mode in which internal rotation of a star depends essentially on
depth and little on latitude: Ω(r,θ) = Ω(r), where r is the mean distance to the stellar center of the considered level surface (or → isobar).
This particular mode was introduced by J.-P. Zahn (1992, A&A 265, 115) to simplify the treatment of rotational → mixing, but also on more physical grounds. Indeed differential rotation tends to be smoothed out in latitude through → shear turbulence. See also → von Zeipel theorem; → meridional circulation .

Etymology (EN): Shellular, the structure of this term is not clear; it may be a combination of → shell (referring to star’s assumed division in differentially rotating concentric shells) + (circ)ular, → circular. The first bibliographic occurrence of shellular is seemingly in Ghosal & Spiegel (1991, On the Thermonuclear Convection: I. Shellular Instability, Geophys. Astrophys. Fluid Dyn. 61, 161). However, surprisingly the term appears only in the title, and nowhere in the body of the article; → rotation.

Etymology (PE): Carxeš, → rotation; puste-yi, adj. of pusté, → shell.

A person who takes care of sheep; a pastor. → shepherd moon.

Etymology (EN): From M.E. shepherde; O.E. sceaphierde, from sceap “sheep” + hierde “herder,” from heord “a herd;” cf. M.L.G., M.Du. schaphirde, M.H.G. schafhirte, Ger. dial. schafhirt.

Etymology (PE): Cupân “shepherd,” variants šobân, šabân; Mid.Pers. šubân, from šu + -bân. The first component from Av. pasu-, fšu- “sheep;” Mid.Pers. pâh, pasvīk “cattle;” Laki and Tâti pas “sheep;”

Kurd. pez/paz; Ossetain (Digor.) fus, (Iron.) fys; Zazaki pes “small cattle;” Lâri pah; Qasrâni cu; Sogd. psw “cattle, sheep;”

cf. Skt. paśu- “cattle;” L. pecu “flock, farm animals, cattle,”
pecunia “money, property;” Goth. faihu “money, fortune;” O.E. feoh “cattle, money;” Ger. Vieh “cattle;” Lith. pekus “cattle;” PIE base *peku- “cattle.” The second component -pân/-bân a suffix denoting “keeper, guard,” sometimes forming agent nouns or indicating relation, → host.

A person who takes care of sheep; a pastor. → shepherd moon.

Etymology (EN): From M.E. shepherde; O.E. sceaphierde, from sceap “sheep” + hierde “herder,” from heord “a herd;” cf. M.L.G., M.Du. schaphirde, M.H.G. schafhirte, Ger. dial. schafhirt.

Etymology (PE): Cupân “shepherd,” variants šobân, šabân; Mid.Pers. šubân, from šu + -bân. The first component from Av. pasu-, fšu- “sheep;” Mid.Pers. pâh, pasvīk “cattle;” Laki and Tâti pas “sheep;”

Kurd. pez/paz; Ossetain (Digor.) fus, (Iron.) fys; Zazaki pes “small cattle;” Lâri pah; Qasrâni cu; Sogd. psw “cattle, sheep;”

cf. Skt. paśu- “cattle;” L. pecu “flock, farm animals, cattle,”
pecunia “money, property;” Goth. faihu “money, fortune;” O.E. feoh “cattle, money;” Ger. Vieh “cattle;” Lith. pekus “cattle;” PIE base *peku- “cattle.” The second component -pân/-bân a suffix denoting “keeper, guard,” sometimes forming agent nouns or indicating relation, → host.

A → natural satellite in orbit near the edge of a → planetary ring, whose → gravitational force on the ring particles strongly controls the distribution of material within the ring, creating ringlets and density waves within the ring and sharp edges at ring boundaries. Examples include → Saturn’s → Prometheus and → Pandora, which shepherd the narrow outer → F ring and the → Uranus satellites → Cordelia and → Ophelia and the epsilon ring. The faster-moving inside satellite accelerates the inner ring particles as it passes them, causing them to spiral out to
larger orbits. At the same time the slower-moving outer satellite decelerates the outer ring particles as they pass by, causing them to spiral inward. The result is a narrow, well-defined ring.

See also: → shepherd; → moon.

A → natural satellite in orbit near the edge of a → planetary ring, whose → gravitational force on the ring particles strongly controls the distribution of material within the ring, creating ringlets and density waves within the ring and sharp edges at ring boundaries. Examples include → Saturn’s → Prometheus and → Pandora, which shepherd the narrow outer → F ring and the → Uranus satellites → Cordelia and → Ophelia and the epsilon ring. The faster-moving inside satellite accelerates the inner ring particles as it passes them, causing them to spiral out to
larger orbits. At the same time the slower-moving outer satellite decelerates the outer ring particles as they pass by, causing them to spiral inward. The result is a narrow, well-defined ring.

See also: → shepherd; → moon.

1. A broad piece of armor carried on the arm as a defense against swords, arrows, etc.
   

2. A person or thing that protects or defends.
   → heat shield; → ozone shield; → self-shielding; → shielding effect.

Etymology (EN): M.E. shelde, from
O.E. scield, scild, related to sciell “seashell, eggshell;”
cf. Du. schild, Ger. Schild, Goth. skildus; PIE base *(s)kel- “to cut.”

Etymology (PE): Separ “shield,” from Mid.Pers. spar “shield;” cf. Skt. phalaka- “board, lath, leaf, shield,” phálati “(he) splits;” Gk. aspalon “skin, hide,” spolas “flayed skin,” sphalassein “to cleave, to disrupt;”
O.H.G. spaltan “to split;” Goth. spilda “board;” PIE base *(s)p(h)el- “to split, to break off.”

1. A broad piece of armor carried on the arm as a defense against swords, arrows, etc.
   

2. A person or thing that protects or defends.
   → heat shield; → ozone shield; → self-shielding; → shielding effect.

Etymology (EN): M.E. shelde, from
O.E. scield, scild, related to sciell “seashell, eggshell;”
cf. Du. schild, Ger. Schild, Goth. skildus; PIE base *(s)kel- “to cut.”

Etymology (PE): Separ “shield,” from Mid.Pers. spar “shield;” cf. Skt. phalaka- “board, lath, leaf, shield,” phálati “(he) splits;” Gk. aspalon “skin, hide,” spolas “flayed skin,” sphalassein “to cleave, to disrupt;”
O.H.G. spaltan “to split;” Goth. spilda “board;” PIE base *(s)p(h)el- “to split, to break off.”

The decrease in attraction between an electron and the nucleus in any atom with more than one → electron shell. The repulsion forces from other electrons in shells cause the net force on electrons in outer shells to be significantly smaller in magnitude. Also known as → screening effect.

See also: → shield; → effect;

The decrease in attraction between an electron and the nucleus in any atom with more than one → electron shell. The repulsion forces from other electrons in shells cause the net force on electrons in outer shells to be significantly smaller in magnitude. Also known as → screening effect.

See also: → shield; → effect;

A change in place or position, in particular
a change in wavelength, causing a movement of a spectral band or line. → redshift; → blueshift.

Etymology (EN): Shift, M.E., from O.E. sciftan “to divide, arrange”; akin to O.N. skipa “to arrange, assign.”

Etymology (PE): Kib “shift” from kibidan “to shift, displace, turn on one side,” kibidé “displaced, turned on one side.”

A change in place or position, in particular
a change in wavelength, causing a movement of a spectral band or line. → redshift; → blueshift.

Etymology (EN): Shift, M.E., from O.E. sciftan “to divide, arrange”; akin to O.N. skipa “to arrange, assign.”

Etymology (PE): Kib “shift” from kibidan “to shift, displace, turn on one side,” kibidé “displaced, turned on one side.”

→ tibia.

Etymology (EN): → tibia

Etymology (PE): Doroštney, literally “big reed,” from dorošt, → macro-, + ney “reed, cane.”

→ tibia.

Etymology (EN): → tibia

Etymology (PE): Doroštney, literally “big reed,” from dorošt, → macro-, + ney “reed, cane.”

1. To emit rays of light.
   

2. Brightness caused by the emission of light.

Etymology (EN): M.E. s(c)hinen (v.); O.E. scinan “shed light, be radiant;” cf.
M.H.G. schinen, O.H.G. skinan; Du. schijnen; Ger. scheinen; Gothic skeinan “to shine, appear;” PIE base *skai- “bright;” cf. Mod.Pers. sâyé “shadow;” Mid.Pers. sâyak “shadow;” Av. a-saya- “throwing no shadow;” Skt. chāya- “shadow;” Gk. skia “shade;” Rus. sijat’ “to shine.”

Etymology (PE): Tâbidan, tâb, → radiate; foruq, → gegenschein.

1. To emit rays of light.
   

2. Brightness caused by the emission of light.

Etymology (EN): M.E. s(c)hinen (v.); O.E. scinan “shed light, be radiant;” cf.
M.H.G. schinen, O.H.G. skinan; Du. schijnen; Ger. scheinen; Gothic skeinan “to shine, appear;” PIE base *skai- “bright;” cf. Mod.Pers. sâyé “shadow;” Mid.Pers. sâyak “shadow;” Av. a-saya- “throwing no shadow;” Skt. chāya- “shadow;” Gk. skia “shade;” Rus. sijat’ “to shine.”

Etymology (PE): Tâbidan, tâb, → radiate; foruq, → gegenschein.

A sharp change in the properties of a gas (density, pressure, temperature).

Etymology (EN): Shock “sudden blow,” from M.Fr. choc “violent attack,” from O.Fr. choquer “to strike against, clash;” cf. Du. schokken “to shake, jolt, jerk.”

Etymology (PE): Toš, from Tabari toš “violent blow,” batoštən “to strike suddenly,” Kurd. tuš “collision,” maybe related to Pers. tuš “strength, vigor;” Av. təviši- “strength,” tavah- “power;” O.Pers. tauman- “power, strength,” tunuvant- “powerful,” from tav- “to have power, to be strong, to be able” (related to tavân “power, strength,” tavânestan “to be powerful, able;” variants tâv, tâb “power”); cf.
Skt. tu- “to be strong, to have authority,” tavas-, tavisa- “strong, energetic,” tavisi- “power, strength.”
Šok, loan from Fr., as above.

A sharp change in the properties of a gas (density, pressure, temperature).

Etymology (EN): Shock “sudden blow,” from M.Fr. choc “violent attack,” from O.Fr. choquer “to strike against, clash;” cf. Du. schokken “to shake, jolt, jerk.”

Etymology (PE): Toš, from Tabari toš “violent blow,” batoštən “to strike suddenly,” Kurd. tuš “collision,” maybe related to Pers. tuš “strength, vigor;” Av. təviši- “strength,” tavah- “power;” O.Pers. tauman- “power, strength,” tunuvant- “powerful,” from tav- “to have power, to be strong, to be able” (related to tavân “power, strength,” tavânestan “to be powerful, able;” variants tâv, tâb “power”); cf.
Skt. tu- “to be strong, to have authority,” tavas-, tavisa- “strong, energetic,” tavisi- “power, strength.”
Šok, loan from Fr., as above.

A burst of very bright → ultraviolet or → soft X-ray radiation expected to occur in → core-collapse supernovae at the instant when the → supernova shock breaks out of the stellar surface. During the collapse of the progenitor → massive star,
the density in the iron core increases drastically. Once the core material reaches → nuclear density, the core rebounds generating a → shock wave that moves outward through the star.
When the shock reaches the outermost layers, it ejects them out into space at → relativistic speeds.

Etymology (EN): → shock; breakout “a forceful escape from being confined or restrained,” from break, from M.E. breken, O.E. brecan (cf. Du. breken, O.H.G. brehhan, Ger. brechen), from PIE base *bhreg- “to break” (see also → fraction) + → out.

Etymology (PE): Borunzani “emergence, evasion,” from borun, → out,

• zani verbal noun of zadan “to strike, beat,” from Mid.Pers. zatan, žatan; O.Pers./Av. jan-, gan- “to strike, hit, smite, kill” (jantar- “smiter”); cf.
  Skt. han- “to strike, beat” (hantar- “smiter, killer”);
  Gk. theinein “to strike;” L. fendere “to strike, push;” Gmc. *gundjo “war, battle;” PIE *g^when- “to strike, kill.”

A burst of very bright → ultraviolet or → soft X-ray radiation expected to occur in → core-collapse supernovae at the instant when the → supernova shock breaks out of the stellar surface. During the collapse of the progenitor → massive star,
the density in the iron core increases drastically. Once the core material reaches → nuclear density, the core rebounds generating a → shock wave that moves outward through the star.
When the shock reaches the outermost layers, it ejects them out into space at → relativistic speeds.

Etymology (EN): → shock; breakout “a forceful escape from being confined or restrained,” from break, from M.E. breken, O.E. brecan (cf. Du. breken, O.H.G. brehhan, Ger. brechen), from PIE base *bhreg- “to break” (see also → fraction) + → out.

Etymology (PE): Borunzani “emergence, evasion,” from borun, → out,

• zani verbal noun of zadan “to strike, beat,” from Mid.Pers. zatan, žatan; O.Pers./Av. jan-, gan- “to strike, hit, smite, kill” (jantar- “smiter”); cf.
  Skt. han- “to strike, beat” (hantar- “smiter, killer”);
  Gk. theinein “to strike;” L. fendere “to strike, push;” Gmc. *gundjo “war, battle;” PIE *g^when- “to strike, kill.”

Any of a series of rings/disks that are formed in a jet flow exhausting a → nozzle when there is a huge difference between the exit pressure and the ambient pressure. At sea level, the exhaust pressure might be lower than the thick atmosphere. In contrast, at very high altitudes, the exhaust pressure might be higher than the thin atmosphere. Shock diamonds can appear just as a rocket is taking off, or at high altitudes when it shifts into → supersonic speed. Shock diamonds are also known as Mach diamonds, → Mach disks, Mach rings, doughnut tails, or thrust diamonds.

See also: → shock; → diamond.

Any of a series of rings/disks that are formed in a jet flow exhausting a → nozzle when there is a huge difference between the exit pressure and the ambient pressure. At sea level, the exhaust pressure might be lower than the thick atmosphere. In contrast, at very high altitudes, the exhaust pressure might be higher than the thin atmosphere. Shock diamonds can appear just as a rocket is taking off, or at high altitudes when it shifts into → supersonic speed. Shock diamonds are also known as Mach diamonds, → Mach disks, Mach rings, doughnut tails, or thrust diamonds.

See also: → shock; → diamond.

The boundary over which the physical conditions undergo an abrupt change because of a → shock wave.

See also: → shock; → front.

The boundary over which the physical conditions undergo an abrupt change because of a → shock wave.

See also: → shock; → front.

A narrow region of abrupt, nearly discontinuous change in the physical characteristics of a medium in which the flow of a fluid changes from subsonic to supersonic. Across a shock wave there is always an extremely rapid rise in pressure, temperature, and density of the fluid.

See also: → shock; → wave.

A narrow region of abrupt, nearly discontinuous change in the physical characteristics of a medium in which the flow of a fluid changes from subsonic to supersonic. Across a shock wave there is always an extremely rapid rise in pressure, temperature, and density of the fluid.

See also: → shock; → wave.

A form of quartz that has a deformed microscopic structure caused by intense pressure which alters the crystalline structure of quartz along planes inside the crystal. It was first discovered after underground nuclear bomb testing. It is found worldwide at the boundary between Cretaceous and Tertiary rocks. This is further evidence (in addition to iridium enrichment) that the transition between the two geological eras was caused by a large meteorite impact.

See also: → shock; → impact.

A form of quartz that has a deformed microscopic structure caused by intense pressure which alters the crystalline structure of quartz along planes inside the crystal. It was first discovered after underground nuclear bomb testing. It is found worldwide at the boundary between Cretaceous and Tertiary rocks. This is further evidence (in addition to iridium enrichment) that the transition between the two geological eras was caused by a large meteorite impact.

See also: → shock; → impact.

Colloquial name for → meteor.

Etymology (EN): Shooting, from shoot (v.); M.E. shoten; O.E. sceotan “to shoot” (cf. O.N. skjota, Du. schieten, Ger. schießen), from PIE base *skeud- “to shoot, to chase, to throw;” → star.

Etymology (PE): Šahâb, → meteor.

Colloquial name for → meteor.

Etymology (EN): Shooting, from shoot (v.); M.E. shoten; O.E. sceotan “to shoot” (cf. O.N. skjota, Du. schieten, Ger. schießen), from PIE base *skeud- “to shoot, to chase, to throw;” → star.

Etymology (PE): Šahâb, → meteor.

1. Having little length. Not tall or high.
   
2. Lasting for only a small amount of time.

Etymology (EN): M.E. schort; O.E. sceort; cf. O.N. skorta “to be short of,” skort “shortness;” O.H.G. scurz “short.”

Etymology (PE): Kutâh “short,” related to kucak “small,” kudak “child, infant;” Mid.Pers. kôtâh “low,” kôtak “small, young; baby;” Av. kutaka- “little, small.”

1. Having little length. Not tall or high.
   
2. Lasting for only a small amount of time.

Etymology (EN): M.E. schort; O.E. sceort; cf. O.N. skorta “to be short of,” skort “shortness;” O.H.G. scurz “short.”

Etymology (PE): Kutâh “short,” related to kucak “small,” kudak “child, infant;” Mid.Pers. kôtâh “low,” kôtak “small, young; baby;” Av. kutaka- “little, small.”

A relatively low → resistance contact, usually accidental, between two points of an → electric circuit with initially different → potential. A short circuit brings about a flow of excess → electric current that can damage the circuit and present a danger for the user.

Etymology (EN): → short; → circuit.

Etymology (PE): Gardrâhband, literally “link, bind, bond in circuit,” from gardrâh, → circuit, + band, → band.

A relatively low → resistance contact, usually accidental, between two points of an → electric circuit with initially different → potential. A short circuit brings about a flow of excess → electric current that can damage the circuit and present a danger for the user.

Etymology (EN): → short; → circuit.

Etymology (PE): Gardrâhband, literally “link, bind, bond in circuit,” from gardrâh, → circuit, + band, → band.

A comet with a period less than 200 years. Same as → periodic comet.

See also: → short; → period; → comet.

A comet with a period less than 200 years. Same as → periodic comet.

See also: → short; → period; → comet.

A variable star that has a relatively short period with respect to stars of similar types.

See also: → short; → period; → variable.

A variable star that has a relatively short period with respect to stars of similar types.

See also: → short; → period; → variable.

1. A deficiency in quantity.
   

   2. The amount of such → deficiency.

Etymology (EN): From → short + suffix -age.

Etymology (PE): Kambud, from kam “little, few, deficient, scarce” + bud, from budan, → exist.

1. A deficiency in quantity.
   

   2. The amount of such → deficiency.

Etymology (EN): From → short + suffix -age.

Etymology (PE): Kambud, from kam “little, few, deficient, scarce” + bud, from budan, → exist.

Same as → Schottky noise; → shot noise.

See also: Translation of Ger. Schroteffekt, from Schrot “small shot, buckshot”

• Effekt; → effect.

Same as → Schottky noise; → shot noise.

See also: Translation of Ger. Schroteffekt, from Schrot “small shot, buckshot”

• Effekt; → effect.

Same as → Schottky noise and → shot effect.

Etymology (EN): → shot effect.

Etymology (PE): → Schottky noise.

Same as → Schottky noise and → shot effect.

Etymology (EN): → shot effect.

Etymology (PE): → Schottky noise.

The upper joint of each of a person’s → arms and the part of the → body between this and the → neck.

Etymology (EN): M.E. schuldre, sholder, shulder, schulder, from O.E. sculdra, sculdor, akin to Du. schouder, Ger. Schulter.

Etymology (PE): Duš “shoulder;” Mid.Pers. dôš “shoulder;” Av. daoš- “shoulder;” cf. Skt. dós- “shoulder.”
Soft “shoulder;” Mid.Pers. suft.

The upper joint of each of a person’s → arms and the part of the → body between this and the → neck.

Etymology (EN): M.E. schuldre, sholder, shulder, schulder, from O.E. sculdra, sculdor, akin to Du. schouder, Ger. Schulter.

Etymology (PE): Duš “shoulder;” Mid.Pers. dôš “shoulder;” Av. daoš- “shoulder;” cf. Skt. dós- “shoulder.”
Soft “shoulder;” Mid.Pers. suft.

→ scapula.

Etymology (EN): → shoulder; blade, M.E.; O.E. blæd “blade of grass;” cognate with Du. blad, Ger. Blatt.

Etymology (PE): Šâné, ketf, → scapula.

→ scapula.

Etymology (EN): → shoulder; blade, M.E.; O.E. blæd “blade of grass;” cognate with Du. blad, Ger. Blatt.

Etymology (PE): Šâné, ketf, → scapula.

1. A brief, abrupt precipitation from a cloud, characterized by the suddenness with which it begins and ends and by the rapid changes in intensity.
   

2. An abundant flow; an outpouring, such as → cosmic-ray shower; → air shower; → meteor shower.

Etymology (EN): M.E. shour; O.E. scur “short fall of rain, fall of missiles or blows;” cf. O.N. skur, O.S., O.H.G. scur, Ger. Schauer.

Etymology (PE): Ragbâr “cloudburst,” from rag “cloudburst; thunder,” → rain + bâr “raining, rain,” from bâridan,
→ rain.
Tondbâr, with tond “fast,” → velocity.

1. A brief, abrupt precipitation from a cloud, characterized by the suddenness with which it begins and ends and by the rapid changes in intensity.
   

2. An abundant flow; an outpouring, such as → cosmic-ray shower; → air shower; → meteor shower.

Etymology (EN): M.E. shour; O.E. scur “short fall of rain, fall of missiles or blows;” cf. O.N. skur, O.S., O.H.G. scur, Ger. Schauer.

Etymology (PE): Ragbâr “cloudburst,” from rag “cloudburst; thunder,” → rain + bâr “raining, rain,” from bâridan,
→ rain.
Tondbâr, with tond “fast,” → velocity.

A → meteor that is part of a group moving in the same orbit around the Sun. → meteor shower.

See also: → meteor; → shower.

A → meteor that is part of a group moving in the same orbit around the Sun. → meteor shower.

See also: → meteor; → shower.

1. A pair of rolling lids that are used to open or close the dome slit. Same as → dome shutter.
   
2. A mechanical device that controls the time during which light is admitted in an optical system.

Etymology (EN): Shutter, from shut (v.), from O.E. scyttan from W.Gmc. *skutjanan + → -er.

Etymology (PE): Bastâr, from bast, past tense stem of bastan

• -âr. Bastan, from Mid.Pers. bastan/vastan “to bind, shut,” Av./O.Pers. band- “to bind, fetter,” banda- “band, tie,” Skt. bandh- “to bind, tie, fasten,” PIE *bhendh- “to bind,” cf. Ger. binden, E. bind, → band. The suffix -âr creates agent nouns (as in xaridâr, virâstâr, foruxtâr, nemudâr, etc.).

1. A pair of rolling lids that are used to open or close the dome slit. Same as → dome shutter.
   
2. A mechanical device that controls the time during which light is admitted in an optical system.

Etymology (EN): Shutter, from shut (v.), from O.E. scyttan from W.Gmc. *skutjanan + → -er.

Etymology (PE): Bastâr, from bast, past tense stem of bastan

• -âr. Bastan, from Mid.Pers. bastan/vastan “to bind, shut,” Av./O.Pers. band- “to bind, fetter,” banda- “band, tie,” Skt. bandh- “to bind, tie, fasten,” PIE *bhendh- “to bind,” cf. Ger. binden, E. bind, → band. The suffix -âr creates agent nouns (as in xaridâr, virâstâr, foruxtâr, nemudâr, etc.).