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: 1301
streak line
  خط ِ خش   
xatt-e xaš

Fr.: ligne d'émission   

In → fluid mechanics, the curve defined by the positions of all particles which have passed through a given point. In laboratory experiments, streak line may be displayed by the stream of color resulting from injection of a dye into the flow.

streak; → line.

stream
  ۱) رابه؛ ۲) رابیدن   
1) râbé; 2) râbidan

Fr.: 1) courant, cours d'eau; 2) couler   

1) (n.) A general term for any river, brook, rivulet or course of running water.
A steady flow of a fluid, small solid particles, or radiant energy. → Magellanic stream. Related concepts: → current (jarayân = جریان); → flow (tacân = تچان).
2) (v.) To move or proceed continuously like a flowing stream.

O.E. stream "a course of water;" cf. O.S. strom, O.N. straumr, Dan. strøm, Swed. ström, Norw. straum, Du. stroom, O.H.G. stroum, Ger. Strom "current, river," from PIE base *sreu- "to flow;" cf. Pers. rud, from Mid.Pers. rôd "river;" O.Pers. rautah- "river;" Skt. srotas- "river," sru- "to flow;" Pali sota- "stream, flood;" Gk. rhoos "a stream, a flowing," from rhein "to flow."

1) Râbé, from dialectal Gilaki râbé "flowing of water or liquid," Semnâni rové "a stream of water flowing beyond control," Pers. colloquial (in râ gereftan "to overflow, flow beyond control"); probably from PIE base *rei- "to flow;" cf. Skt. ray- "to flow, run," raya- "stream;" L. rivus "stream, brook;" O.C.S. reka "river;" M.Ir. rian "river, way;" Goth. rinnan "run, flow," rinno "brook;" M.L.G. ride "brook;" O.E. riþ "stream."
2) Râbidan infinitive of râbé.

stream current
  جریان ِ رابه   
jarayân-e râbé

Fr.: veine de courant   

Hydrology: A steady current in a stream or river.
Oceanography: A deep, narrow, well-defined fast-moving ocean current.

stream; → current.

stream filament
  رشته‌ی ِ رابه   
rešte-ye râbé

Fr.:   

A → stream tube with a small cross section so that the variation of velocity over it is negligible.

stream; → filament.

stream tube
  لوله‌ی ِ رابه   
lule-ye râbé

Fr.: tube de courant   

A pipe-shaped volume obtained by drawing → streamlines through every point of a closed curve in the fluid. Since the stream tube is bounded on all sides by streamlines and since, by definition, there can be no velocity across a streamline, no fluid may enter or leave a stream tube, except through its ends. See also → stream filament.

stream; → tube.

streamer
  درفشک   
derafšak

Fr.: jet, grand jet   

Any long, narrow piece or thing, as a spray of a plant or a strip of cloud; something that streams. → coronal streamer; → helmet streamer

M.E. stremer, from → stream + -er.

Derafšak, from derafš "flag, banner;" Mid.Pers. drafš "banner;" Av. drafša- "banner;" cf. Skt. drapsá- "flag, banner; drop, spark;" also Fr. drapeau; It. drappo "flag;" Lith. drapana "dress."

streaming
  رابش   
râbeš

Fr.: 2) lecture en transit   

1) Fluid mechanics: Any process or instance of flowing.
2) Computer science: A condition of a terminal or modem that has locked into a constant carrier signal, thus preventing the normal flow of data.

Verbal noun of → stream.

streamline
  راب‌خط   
râbxatt

Fr.: ligne de courant   

An imaginary continuous curve drawn in a fluid so that the tangent at every point of it at any instant of time coincides with the direction of the motion of the fluid at that point. The component of velocity at right angles to the streamline is always zero. If a number of streamlines is considered at a particular instant, the pattern they form gives a good indication of the flow then occurring. Same as → flow line. See also → path line, → stream tube.

stream; → line.

Strehl ratio
  وابر ِ اشترل   
vâbr-e Strehl

Fr.: rapport Strehl   

The ratio of the peak intensity of the central core of the image of a point source to the corresponding intensity contained in an image obtained in the absence of aberration. An optically perfect system has a Strehl ratio of unity. The ratio may be computed by integrating the area under a → modulation transfer function (MTF) curve and dividing it by the integral over the diffraction-limited MTF.

In honor of Karl Strehl (1864-1940), the German physicist and mathematician who introduced the concept; → ratio.

strength
  زور   
zur (#)

Fr.: force, intensité, résistance   

The quality or quantity of force, power, resistance, etc. → line strength.
Mechanics: The ability of a material to resist → stress without yielding or fracture.

M.E., from O.E. strengþu "power, force, vigor, moral resistance," (cf. O.H.G. strengida "strength"), noun of strong.

Zur "strength," variant zâvar; Mid.Pers. zôr "strength, power, vigour," zâvar "strength, force," zôrik "powerful," loaned in Arm. zaur; Av. zāvar- "strength."

strength of materials
  زور ِ مادیگ‌ها   
zur-e mâdighâ

Fr.: résistance des matériaux   

The science concerned with physical characteristics (stress, strain, strength, stiffness, stability) of various engineering components and structures when forces are applied on them.

strength; → material.

stress
  خشر   
xošar

Fr.: contrainte   

The force acting across a unit area in a solid body, tending to produce → strain in the body or part of it. When a stress is applied to a body, the ratio of stress to strain is a characteristic constant of the body. See also → shear.

Stress "hardship, adversity, force, pressure," in part a shortening of M.Fr. destresse (fr. détresse) in part from O.Fr. estrece "narrowness, oppression," from L. strictus "compressed," p.p. of stringere "draw tight."

Xošar variant of fešâr "pressure," cf. Lori xošâr, Aftari xešâr, Qazvini, Qomi xošâl, Tabari qošâr Khotanese ssarr- "to exhilarate;" loaned in Arm. ôšarak, in Ar. afšaraj "juice."

stretch
  درگیدن   
dargidan

Fr.: étirer   

To make something longer or wider by pulling it.

M.E. strecchen, from O.E. streccan; cf. Dan. strække, Sw. sträcka, O.Fris. strekka, O.H.G. strecchan, M.L.G., M.Du., O.H.G., Ger. strecken "to stretch"), perhaps a variant of the root of stark, or from PIE root *strenk- "tight, narrow; pull tight, twist," → strain.

Dargidan, from darg "long" (Zâzâ, Ossetic), variants derâz, derež "long" (→ longitude); Mid.Pers. drâz "long;" O.Pers. darga- "long; " Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "long (in space and time);" PIE *dlonghos- "long."

stretching term
  ترم ِ درگش   
tarm-e dargeš

Fr.: terme d'étirement   

The second term of the right-hand side in the → induction equation. This term is at the origin of the → dynamo effect and also of the → Alfven waves when in the presence of a mean field.

stretch; → term.

strewn field
  میدان ِ پخش   
meydân-e paxš

Fr.: champ d'éparpillement   

The area over which the → meteorite fragments from a particular → fall are dispersed.

Strewn, p.p. of strew, from M.E. strewen, O.E. strewian; cf. O.S. stroian, O.N. stra, Dan. strø, Swed. strö, M.Du. strowen, Du. strooien, O.H.G. strouwen, Ger. streuen, Goth. straujan "to sprinkle, strew;" PIE base *stere- "to spread, extend, stretch out;" from which Pers. gostar-, gostardan "to stretch, expand;" Av. star- "to spead out;" → field.

Meydân, → field; paxš "scattered," → diffuse.

stria
  خش   
xaš (#)

Fr.: stria   

Secondary synchrones that originate at a certain point in some comets' dust tail, a point where for some reason the dust particles have fragmented.

Mod.L. stria "strip, streak," L. "furrow, channel;" cognate with Du. striem, O.H.G. strimo, Ger. Strieme "stripe, streak," from PIE base *streig- "to stroke, rub, press."

Xaš "streak," dialectal Qomi xaš "streak, stria, mark," Yaqnavi xaš "to draw," Lori kerr "line;" litterary Pers. xattline; Mid/Mod.Pers. kešidan, kašidan "to draw, protract, trail, drag, carry;" Av. karš- "to draw; to plow," karša- "furrow;" Proto-Iranian *kerš-/*xrah- "to draw, plow;" cf. Skt. kars-, kársati "to pull, drag, plow;" Gk. pelo, pelomai "to move, to bustle;" PIE base kwels- "to plow."

string
  تار، ریسمان   
târ, rismân

Fr.: corde   

1) General: A thin cord, usually made of twisted fibers, used for fastening, hanging, or tying. Something that resembles string in form or texture.
2) Music: A cord stretched across a musical instrument and vibrated to produce sound.
3) Subatomic string; → string theory.
4) → cosmic string.

M.E. string, streng; O.E. streng "line, cord, thread;" Du. streng,Ger. Strang "rope, cord;" PIE base *strenk- "stiff, tight."

Târ "thread, warp, string" (related to tur "net, fishing net, snare," tâl "thread" (Borujerdi dialect), tân "thread, warp of a web," from tanidan, tan- "to spin, twist, weave;" Mid.Pers. tanitan; Av. tan- to stretch, extend;" cf. Skt. tan- to stretch, extend;" tanoti "stretches," tántra- "warp; essence, main point;" Gk. teinein "to stretch, pull tight;" L. tendere "to stretch;" Lith. tiñklas "net, fishing net, snare," Latv. tikls "net;" PIE base *ten- "to stretch").
Rismân "thread, string, cord" variants rasan, ras, ris, razé, rajé, rijé, rešmé, Mid.Pers. rasan, cf. Skt. rajju- "rope, cord," L. restis "cord," Lith. resgis, rekstis "wicker basket," O.L.G. risch; PIE base *rezg- "to plait."

string theory
  نگره‌ی ِ ریسمان   
negare-ye rismân

Fr.: théorie des cordes   

The latest theory of fundamental physics in which the basic entity is a one-dimensional → brane rather than the "zero-dimensional" point of conventional elementary particle physics. The one-dimensional string-like objects exist in the normal four dimensions of → space-time plus additional dimensions, the total dimensions being ten, eleven, or twenty-six depending on the version of the theory. Particles are strings that vibrate in different ways to account for their various properties.

string; → theory.

strip
  ۱) نوار؛ ۲) لخت‌کردن   
1) navâr; 2) loxt kardan

Fr.: 1) bande; 2) désabiller, décaper, démonter   

1) A long, flat, narrow piece of something. → instability strip.
2) To deprive of covering; to deprive of clothing; make bare or naked. → ram pressure stripping.

1) M.E. probably from M.L.G. strippe "strap, thong," related to stripe.
2) M.E. strippe, O.E. *stryppan; cf. M.Du. stropen "to strip off, to ramble about plundering," O.H.G. stroufen "to strip off, plunder," Ger. streifen "strip off, to ramble, roam, rove."

1) Navâr "strip."
2) Loxt kardan "to strip, to deprive of," from loxt "naked, deprived of," variants rut, lut, rud "plucked, stripped of its feathers (a bird) or of its wool (a lamb);" cf. Kurd. we-rutin "to pluck, strop off;" Proto-Ir. *rauH "to pluck, pull out;" IE cognates Lith. liautis "to be cut off, mutilated;" O.H.G. , E. lye (Cheung 2007)

Stromgren sphere
  سپهر ِ استرومگرن، کره‌ی ِ ~   
sepehr-e Stömgren, kore-ye ~

Fr.: sphère de Strömgren   

A theoretical sphere of → ionized hydrogen created by energetic → ultravioletphotons of a hot, → massive star embedded in a uniform interstellar → molecular cloud and lying at the center of the sphere. → H II region.

Named after Bengt Strömgren (1908-1987), a Danish astrophysicist, who put forward the first and simplest version of the model in 1939; → sphere.

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