An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 1279
skylight
  نور ِ آسمان   
nur-e âsmân-e

Fr.: lumière du ciel   

Solar radiation which reaches the observer from the general sky. It is sunlight which has undergone multiple scattering events with the molecules of the Earth's atmosphere (Rayleigh scattering) or with clouds or other aerosols in the atmosphere. High levels of skylight reduce the contrast of a shadow. Also known as diffuse skylight, diffuse sky radiation.

sky; → light.

slab
  تیات   
tiyât

Fr.: dalle   

A broad, flat, somewhat thick piece of stone, wood, or other solid material (Dictionary.com).

M.E sclabbe, slabbe of unknown origin, maybe related to O.Fr. escopel, escalpe "thin fragment of wood."

Tiyât, from Kurd. (Ilâm) teyat "slab."

slash
  اسلش   
eslaš

Fr.: barre oblique, slash   

An oblique line (/) used between alternatives (e.g. and/or), in fractions (e.g. 4/5), or in percent ratios (e.g. kilometer/hour).

From M.E. slaschen, perhaps from M.Fr. esclachier "to break," variant of esclater "to break, splinter."

Eslaš, loan from E.

slate
  پلمه   
palmé (#)

Fr.: ardoise   

A fine-grained rock formed by the metamorphosis of clay, shale, etc., that tends to split along parallel cleavage planes, usually at an angle to the planes of stratification (Dictionary.com).

M.E. sclate, from M.Fr. esclate, feminine of esclat "piece split off," (Fr. éclat) so called because the rock splits easily into thin plates.

Palmé "slate," "a board on which children learn to read," ultimately from Proto-Ir. *parn-, *parm- "feather," PIE *pernom-, *pornos- "feather," → tablet.

sleet
  تنگر   
tangar

Fr.: grésil   

Precipitation in the form of → transparent or → translucent ice → pellets that are 5 mm or less in diameter, created by the freezing of rain as it falls (distinguished from hail).

M.E. slete; akin to M.H.G. sloz, M.L.G. sloten (plural) "hail."

Tangar, from Gilaki tangar "fine hail."

slepton
  اسلپتون   
slepton

Fr.: slepton   

In → supersymmetry theories, a hypothetical → boson super-partner of a → lepton. See also → squark

s from → supersymmetry; → lepton.

slewing
  تند-رانش   
tond-râneš

Fr.: déplacement rapide   

The action of rapidly moving a telescope in the alpha or delta direction under computer control as it moves to point at a new position in the sky.

Slew "to turn, swing, twist," earlier slue a nautical word, of unknown origin.

Tondrâneš, literally "driving fast," from tond "swift, rapid, brisk; fierce, severe" (Mid.Pers. tund "sharp, violent;" Sogdian tund "violent;" cf. Skt. tod- "to thrust, give a push," tudáti "he thrusts;" L. tundere "to thrust, to hit" (Fr. percer, E. pierce, ultimately from L. pertusus, from p.p. of pertundere "to thrust or bore through," from per- + tundere, as explained); PIE base *(s)teud- "to thrust, to beat") + râneš, verbal noun of rândan "to push, drive, cause to go," causative of raftan "to go, walk, proceed" (present tense stem row-, Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").

slewing drive
  موتور ِ تند-رانش   
motor-e tond-râneš

Fr.: moteur de déplacement rapide   

A motor designed to drive a high-speed radar antenna for slewing to monitor a target.

slewing; → drive

slice
  ۱) قاچ؛ ۲) قاچیدن   
1) qâc (#); 2) qâcidan

Fr.: 1) tranche; 2) trancher   

1) A thin, broad piece cut from something.
2) To cut into slices; divide into parts (Dictionary.com).

O.Fr. escliz "splinter, fragment" (Fr. éclisse), a back-formation from esclicier "to splinter, shatter, smash;" cf. O.H.G. slihhan.

Qâc, contraction of qârc, from karj "slice, a slice of melon; a piece cut out of the collar of a garment;" ultimately from Proto-Ir. *kartaka-, from *kart- "to cut," cf. Av. karət- "to cut;" Skt. kart- "to cut," karəta- "knife;" Mid.Pers. kârt, → knife.

slingshot effect
  اُسکر ِ فلاخن   
oskar-e falâxan

Fr.: effet de fronde gravitationnelle, gravidéviation   

An important astronautical technique whereby a spacecraft takes up a tiny fraction of the gravitational energy of a planet it is flying by, allowing it to change trajectory and speed. Also known as → gravitational slingshot or → gravitational assist.

Slingshot, from sling, from M.E. slyngen, from O.N. slyngva "to sling, fling" + shot, from M.E., from O.E. sc(e)ot, (ge)sceot; cf. Ger. Schoss, Geschoss; → effect.

Oskar, → effect; falâxan "sling;" from Av. fradaxšana- "sling," fradaxšanya- "sling, sling-stone;"

slit
  شکاف   
šekâf (#)

Fr.: fente   

A long, thin opening in a spectrograph allowing only the light studied to fall on the prism.

O.E. slitan "to cut or tear up, slit;" cf. O.S. slitan, O.N. slita, M.L.G., M.Du. sliten, Du. slijten, O.H.G. slizan, Ger. schleißen "to slit."

Šekâf "slit," from Mod./Mid.Pers. škâf- škâftan "to split, burst;" Proto-Iranian *kap-, *kaf- "to split;" cf. Gk. skaptein "to dig;" L. cabere "to scratch, scrape," P.Gmc. *skabanan (Goth. skaban; Ger. schaben; E. shave). PIE base *(s)kep- "to cut, to scrape, to hack."

slit spectrograph
  بیناب‌نگار ِ شکاف‌مند   
binâbnegâr-e šekâfmand

Fr.: spectrographe à fente   

A type of spectrograph that uses a slit to provide resolution.

slit; → spectrograp.

slitwidth
  شکاف-پهنا   
šekâf-pahnâ

Fr.: largeur de fente   

The width size of the slit which determines the spectral resolution of a spectrograph.

slit; → width.

slope
  شیب   
šib (#)

Fr.: pente   

1) An inclined surface; deviation from the horizontal or vertical.
2) The tangent of the angle formed by the intersection of a given straight line and the X-axis of a system of Cartesian coordinates.
3) The derivative of the function whose graph is a given curve evaluated at a designated point.
4) The exponent of the → initial mass function . See also → Salpeter slope.
5) → slope parameter.

From M.E. aslope (adv.) "on the incline," from O.E. *aslopen, p.p. of aslupan "to slip away," from a- "away" + slupan "to slip."

Šib "slope, descent, declivity," contraction of nešib, našib "declivity, descent; lowness of ground, slope of any place;" Mid.Pers. nišēp "declivity, (astrology) dejection," Av. *nixšvaēpā-, xšvaēpā- "bottom, rear."

slope parameter
  پارامون ِ شیب   
pârâmun-e šib

Fr.: paramètre de pente   

In a → power-law distribution or → regression, the → exponent that represents the effect of the → independent variable, x, on the → dependent variable, y. X has no association with y if the slope parameter = 0 and x has strong association with y if the slope parameter is large.

slope; → parameter.

slow
  آهسته   
âhesté (#)

Fr.: lent   

Moving or proceeding with little or less than usual speed or velocity.

O.E. slaw "inactive, sluggish;" cf. O.S. sleu "blunt, dull," M.Du. slee, Du. sleeuw "sour, blunt," O.H.G. sleo "blunt, dull," O.N. sljor, Dan. sløv, Swed. slö "blunt, dull."

Âhesté "slow, quiet, tender, soft," ultimately from Proto-Iranian *ā-hasta-ka-, literally "at rest, motionless, seated." The first and third components are affixes, the main component from *had- "to "sit, be seated;" cf. Av. had- "to sit" (nī...hazdiiāt "would sit down"); Pers. nešastan "to sit;" PIE base *sed- "to sit;" cf. Skt. sad- to sit," sidati "sits;" Gk. hezomai "to sit," hedra "seat, chair;" L. sedere "to sit;" O.Ir. suide "seat, sitting;" Welsh sedd "seat;" Lith. sedmi "to sit;" Rus. sad "garden;" Goth. sitan, Ger. sitzen; E. sit.

slow neutron
  نوترون ِ آهسته   
notron-e âhesté (#)

Fr.: neutron lent   

A neutron whose kinetic energy does not exceed about 10 electron-volts. Also called → thermal neutron.

slow; → neutron.

slow nova
  نو-اختر ِ آهسته   
now-axtar-e âhesté

Fr.: nova lente   

A type of nova whose light curve exhibits a characteristically slow development, having a rise time of several days, maximum of several weeks, and slower decline.

slow; → nova.

Slowly Pulsating B star (SPB)
  ستاره‌ی ِ آهسته تپنده‌ی ِ گونه‌ی ِ B   
setâre-ye âhesté tapande-ye gune-ye B

Fr.: étoile B pulsante à longue période   

A member of a class of → B stars that are situated along the → main sequence with → spectral types ranging from B2 to B9 and masses from 3 to 7 → solar masses. In the → H-R diagram the SPB group lies below → beta Cephei variables, which are more massive. SPBs show light and line-profile variations that are multi-periodic with periods of the order of days. This variability is understood in terms of non-radial → stellar pulsations, and their → oscillation modes are high-order → g modes. Theoretical models attribute the pulsational nature of SPBs to the → kappa mechanism, acting in the metal → opacity bump at 2 x 105 K. Their g-mode pulsations penetrate deep into the stellar interior, making these objects very promising for → asteroseismology. Several oscillation modes are excited simultaneously, resulting in periodicities on time scales of the order of months or even years. The prototype of this group is 53 Per. First introduced as a distinct class by Waelkens (1991, A&A 246, 453).

slow; → pulsating; → B star.

slug
  لیسک   
lisak (#)

Fr.: limace   

A worm-like gastropod that is related to the → snail family but has no shell.

M.E. slugge "sluggish," probably from Scandinavian; cf. dialectal Norwegian sluggje "heavy, slow person."

Lisak dialectal Tabari (also see Dehxodâ)

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