An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1333
Stokes law
  قانون ِ استوکس   
qânun-e Stokes (#)

Fr.: loi de Stokes   

1) Fluid mechanics: At low velocities, the frictional force on a spherical body moving through a fluid at constant velocity is equal to 6πaην, where a is the radius of the sphere, η the fluid viscosity, and ν the velocity.
2) Spectroscopy: The wavelength of luminescence excited by radiation is always greater than that of the exciting radiation.

After Sir George Gabriel Stokes (1819-1903), a British mathematician and physicist, who made important contributions to fluid dynamics, optics, and mathematical physics; → law

Stokes parameters
  پارامون‌های ِ استوکس   
pârâmunhâ-ye Stokes

Fr.: paramètres de Stokes   

Four parameters which are needed to fully describe the → polarization state of → electromagnetic radiation. They involve the maximum and minimum intensity, the ellipticity, and the direction of polarization. The four Stokes parameters are traditionally defined as follows:
I ≡ total intensity.
Q ≡ I0 - I90 = difference in intensities between → horizontal and → vertical  → linearly polarized components.
U ≡ I+45 - I-45 = difference in intensities between linearly polarized components oriented at +45° and -45° (or 135°).
V ≡ Ircp - Ilcp = difference in intensities between right and left → circularly polarized polarized components.

Stokes law; → parameter.

sang (#)

Fr.: pierre   

The hard nonmetallic mineral or group of consolidated minerals either in mass or in a fragment of pebble or larger size. See also → rock.

O.E. stan; cf. O.N. steinn, Dan. steen, O.H.G., Ger. Stein; from PIE *stai- "stone," also "to thicken, stiffen" (cf. Skt. styayate "curdles, becomes hard;" Av. stay- "heap;" Gk. stear "fat, tallow," stia, stion "pebble").

Sang "stone, rock;" Mid.Pers. sang; O.Pers. aθanga-; Av. asenga- "stone;" PIE *aken-.

Stone Age
  عصر ِ سنگ   
asr-e sang (#)

Fr.: âge du fer   

A prehistoric period during which the main material used to make tools and weapons was stone. The Stone Age is usually divided into three separate periods (Paleolithic Period, Mesolithic Period, and Neolithic Period) based on the degree of sophistication in the fashioning and use of tools. The Paleolithic time period is by far the longest, beginning some two million years ago and ending around 10,000 BC to coincide with the end of the last ice age (Pleistocene epoch).

stone; → age.

stony meteorite
  شخانه‌ی ِ سنگی   
šaxân-ye sangi

Fr.: météorite pierreuse   

A meteorite composed largely of rock-forming (→ silicate) → minerals. Stony meteorites are the most abundant kind, about 95%, of all meteorites. They are divided into two groups: → chondrites and → achondrites.

stone; → meteorite.

stony-iron meteorite
  شخانه‌ی ِ سنگی-آهنی   
šaxâne-ye sangi-âhani

Fr.: sidérolithe, sidérolite   

Meteorites comprised of roughly equal amounts of → nickel/→ iron and → stone. They are divided into two groups: → pallasites and → mesosiderites. The stony-irons are thought to have formed at the core/mantle boundary of their parent bodies. The stony-irons account for less than 2% of all known meteorites. Also called → siderolite.

stony; → iron; → meteorite.

  ۱) بازداشتن؛ بازداشت؛ ۲) دریچه   
1) bâzdâštan; bâzdâšt (#); 2) daricé; (#)

Fr.: diaphragme   

1) To hinder or prevent the passage of. → stopping power.
2) The diaphragm used in optical instruments to cut off the marginal portions of a beam of light passing through lenses. → field stop; → stop number.

M.E. stoppen (v.), O.E. -stoppian (in forstoppian "to stop up, stifle"); V.L. *stuppare "to stop or stuff with tow or oakum" (cf. It. stoppare, Fr. étouper "to stop with tow"), from L. stuppa "coarse part of flax, tow."

1) Bâzdâštan, bâzdâšt- "to stop, restrain, inhibit, coerce, detain," from bâz-, → re-, + dâštan "to have, hold, maintain, possess," → access.
2) Daricé, literally "small door; window," from dar "door," + -cé diminutive suffix. Dar "door," Mid.Pers. dar, O.Pers. duvara-, Av. dvar-, cf. Skt. dvár-, Gk. thura, L. fores, P.Gmc. *dur-, O.E. duru, E. door, Lith. dvaras "court-yard;" PIE *dhwer-/*dhwor- "door, gate."

stop consonant
  هم‌آوای ِ ایستی   
hamâvâ-ye isti

Fr.: consonne occulsive   

occlusive consonant.

stop; → consonant.

stop number
  وابر ِ کانونی   
vâbar-e kânuni

Fr.: rapport focal   

Same as → focal ratio.

stop; → ratio.

Vâbar, → ratio; kânuni, → focal.

stopping power
  توان ِ بازداشت   
tavân-e bâzdâšt

Fr.: pouvoir d'arrêt   

A quantity indicating the extent with which a substance absorbs a → charged particle passing through it. It is the energy lost by a → non-relativistic particle per unit length of its path in the substance.

stop; → power.

  رهاواژ، فکن‌واژ   
rahâ-vâž, fekan-vâž

Fr.: mot vide   

Computers: A very commonly used word that is normally excluded by computer search engines. Stopwords have very little informational content, such as: and, the, of, it, as, may, that, a, an, of, off, etc.

stop; → word.

Rahâ-vâž, literally "free word," from rahâ "free, set free" (O.Pers. rad- "to leave," Skt. rah-, rahati "separates, leaves," Av. razah- "isolation;" PIE *redh-) + vâž, vâžé, → word. Fekan-vâž, literally "dropped word," from fekan present stem of fekandan, afkandan "to throw, cast away;" Mid.Pers. abgandan "to throw;" O.Pers. avakan- "to throw, place on," from Proto-Iranian *kan- "to throw, place, put."

tufân (#)

Fr.: orage   

An atmospheric disturbance with strong winds accompanied by rain, snow, or other precipitation and often by thunder and lightning.
A violent disturbance or upheaval.

M.E, from O.E. storm; cf. O.S., M.L.G., M.Du., Du. storm, O.H.G., Ger. sturm.

Tufân "storm; the roaring of the sea; noise, confused hum of men or animals," Lori tufo, Laki tuf "intense shower accompanied by wind," from tufidan "to roar, raise a tumult."

dâstân (#)

Fr.: conte, histoire   

A narrative, either true or fictitious, in prose or verse, designed to interest, amuse, or instruct the hearer or reader; tale (

M.E. storie, from O.Fr. estorie, estoire "story, chronicle, history," from L.L. storia, shortened from L. historia "history, account, tale, story," → history.

Dâstân "story, fable, romance."


Fr.: traînard   

One who moves along slowly so as to remain some distance behind the person or people in front. → blue straggler.

From straggle "to wander from the proper path, to rove from one's companions," from M.E. straglen "to wander."

Veylân "wanderer, vagabond," of unknown origin, may be related to yalé "turned loose, vagabond, allowed to pasture at liberty, rover," or vel "set free."

râst (#)

Fr.: droit   

Free from a bend, angle, or curve. → straight line.

M.E. streght, straight, from p.p. of strecchen, → stretch.


straight line
  خط ِ راست   
xatt-e râst (#)

Fr.: droite   

A line without curvature or angles. A line whose → slope is → constant.

straight; → line.


Fr.: déformation   

Change of volume and/or shape of a body, or part of a body, due to an applied → stress. When a body is deformed by such a force, through compression or distension, the strain is the ratio of the dimensional change to the original or un-strained dimension. The strain may be a ratio of lengths, areas, or volumes. See also → shear.

M.E. streinen (v.), from O.Fr. estreindre "to bind tightly, clasp, squeeze," from L. stringere "to bind or draw tight," from PIE base *strenk- "tight, narrow; pull tight, twist;" cf. Gk. strangein "twist;" Lith. stregti "congeal;" O.H.G. strician "mends nets;" Ger. stramm, Du. stram "stiff."

Šepil "squeeze; fondness" (Dehxodâ) of unknown origin.

šegeft (#)

Fr.: étrange   

Unusual, not expected, extraordinary. → strange particle.

M.E., from O.Fr. estrange "foreign, alien," from L. extraneus "foreign, external," from extra "outside of," → extra-.

Šegeft, from Mid.Pers. škaft, škift, škuft "strange, wonderful, amazing;" Av. skapta- "wonderful."

strange particle
  ذره‌ی ِ شگفت   
zarre-e šegeft

Fr.: particule étrange   

An elementary particle created in high-energy particle collisions having a short life and a strangeness quantum number of 1. For example, sigma and xi baryons are strange particles. A strange particle is produced when a strange quark is created in a high-energy collision. → strangeness.

strange; the concept of "strange" arose from the observation that these particles decay rapidly, in contrast to others that do not. → particle.

šegefti (#)

Fr.: étrangeté   

A quantum number used to describe certain short-lived particles. It is defined as the number of strange anti-quarks minus the number of strange quarks in a particle. Strangeness is conserved in any strong and electromagnetic interaction, but not in weak interactions.

Strangeness, the quality or condition of being → strange.

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