# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 742
 Riemann's geometry   هندسه‌ی ِ ریمان   hendese-ye RiemannFr.: géométrie de Riemann   Same as → Riemannian geometry.→ Riemannian; → geometry. Riemannian   ریمانی   Riemanni (#)Fr.: riemannien   Of or pertaining to Georg Friedrich Bernhard Riemann (1826-1866) or his mathematics findings. → Riemannian geometry, → Riemannian manifold, → Riemannian metric, → Riemann problem, → Riemann curvature tensor.After the German mathematician Georg Friedrich Bernhard Riemann (1826-1866), the inventor of the elliptic form of → non-Euclidean geometry, who made important contributions to analysis and differential geometry, some of them paving the way for the later development of → general relativity. Riemannian geometry   هندسه‌ی ِ ریمانی   hendese-ye RiemanniFr.: géométrie riemannienne   A → non-Euclidean geometry in which there are no → parallel lines, and the sum of the → angles of a → triangle is always greater than 180°. Riemannian figures can be thought of as figures constructed on a curved surface. The geometry is called elliptic because the section formed by a plane that cuts the curved surface is an ellipse.→ Riemannian; → geometry. Riemannian manifold   بسلای ِ ریمانی   baslâ-ye RiemanniFr.: variété riemannienne   A → manifold on which there is a defined → Riemannian metric (Douglas N. Clark, 2000, Dictionary of Analysis, Calculus, and Differential Equations).→ Riemannian; → metric. Riemannian metric   متریک ِ ریمانی   metrik-e RiemanniFr.: métrique riemannienne   A positive-definite inner product, (.,.)x, on Tx(M), the tangent space to a manifold M at x, for each x  ∈ M, which varies continually with x (Douglas N. Clark, Dictionary of Analysis, Calculus, and Differential Equations).→ Riemannian; → metric. rift   چاک، گسل‌دره   câk, gosal-darréFr.: rift; fissure, crevasse   1) General: a gap or break made by splitting, cleaving, etc.; fissure; cleft. 2) Geology: A narrow cleft, fissure, or other opening in rock, made by cracking or splitting. 3) Geology: An elongated trough in the Earth's crust bounded by → faults.M.E., from a Scandinavian source; cf. Dan., Norw. rift "a cleft."1) Câk "fissure, rupture, cleft, crack," related to caqidan "to drive a nail, strike together, fix a spike;" caxidan "to quarrel, strive;" diatectal Shughni cuγ, Roshani coγ "breaking, tearing, ripping up;" Malâyeri ceqidan "cracking of a cold porcelain bowl when receiving hot water;" Yazghulami cok-, coxt "to pound, to stamp;" Wakhi cuk-, cukt "to strike;" Ossetic cædyn "to shake, strike iron;" Lori cok "a mark fixed to separate two grounds;" Sogd. cax "to battel, fight;" Mid.Pers. (prefixed) pacên "copy" (see also Cheung 2007). Gosal-darré, from gosal, → fault, + darré, → valley. rift valley   گسل‌دره   gosal-darréFr.: fossé d'effondrement, ~ tectonique   A long, narrow valley formed by the lowering of land between two → faults. Also called → graben.→ rift; → valley. Rigel (β Ori)   رجل   Rejl (#)Fr.: Rigel   The brightest star in the constellation → Orion (visual magnitude 0.18). A → blue supergiant of type B8 Iab with an initial mass of 17 solar masses, Rigel is 773 light-years away, and actually shines with the light of 40,000 Suns. It is accompanied by a fairly bright, seventh magnitude companion nine seconds of arc apart. The companion is itself double, the components much fainter and much less massive → main sequence stars of type B.Rigel "foot," short for Ar. rijl al-jauza' (رجل‌الجوزاء) "the foot of jauza'." The latter word means "the manifest one," initially "black sheep with white middle." The Gk. figure was translated as such because of its conspicuousness among other constellations.Rejl, from Ar., as above. Rigel Kentaurus   پای ِ کنتاؤروس   Pâ-ye KentawrosFr.: Rigil Kentaurus   Same as the star → Alpha Centauri.From Ar. Rijl al-Qanturis "foot of Centaurus," from rijl "foot," + Qanturis Arabicized → Centaurus.Pâ-ye Kantawros, "foot of Centaurus," from pâ, → foot, + Kentawros, → Centaurus. right   ۱) راست؛ ۲) درست؛ ۳) راشن   1) râst (#); 2) dorost; 3) râšanFr.: droit   1a) Straight, free from curves, angles, or irregularities. → right ascension. 1b) Opposite of → left. → right-hand rule, → right-hand screw rule. 2) In accordance with fact, reason, or truth; correct or true. 3) Something that a person is or should be morally or legally allowed to have, get, or do (Merriam-Webster).M.E.; O.E. reht, riht; cf. O.H.G. reht, Ger. recht, O.N. rettr, Goth. raihts; P.Gmc. *rekhtaz, cognate with Pers. râst, as below.1) Râst "right, true; just, upright, straight;" Mid.Pers. râst "true, straight, direct;" Soghdian rəšt "right;" O.Pers. rāsta- "straight, true," rās- "to be right, straight, true;" Av. rāz- "to direct, put in line, set," razan- "order;" related to Mid.Pers. rây-, râyênitan "to arrange;" Mod.Pers. raj "line, row," variants raž, rak, râk, rezg (Lori), radé, râdé "line, rule, row," rasté, râsté "row, a market with regular ranges of shops;" ris, risé "straight;" cf. Skt. raj- "to direct, stretch," rjuyant- "walking straight;" Gk. orektos "stretched out;" L. regere "to lead straight, guide, rule," p.p. rectus "right, straight;" PIE base *reg- "move in a straight line," hence, "to direct, rule;" 2) Dorost "correct, whole, complete, healthy," → integral. 3) Râšan, related to râst, as above; cf. Mid.Pers. Rašn "Justice deity; calendar 18th day;" Av. rašnu- "the Zoroastrian Justice deity, orientation." right angle   زاویه‌ی ِ راست   zâviye-ye râstFr.: angle droit   An angle of 90°.→ right; → angle. right ascension   راست‌افراز   râst afrâz (#)Fr.: ascension droite   A coordinate in the → equatorial system measured from the → vernal equinox eastward to the point where the object → hour circle intersects the → celestial equator. Right ascension (symbol α) is expressed in hours, minutes, and seconds. See also: → declination.→ right; ascension, M.E. ascencioun, from O.Fr., from L. ascendere "to climb up," from → ad- "to" + scandere "to climb."Râst, → right; afrâz present stem of afrâzidan, afrâštan "to raise, exalt, extole," from Mid.Pers. abrâstan, abrâz- "to lift, raise," from ab-, from O.Pers./Av. abiy-/aiwi- "to, upon, against;" cf. Skt. abhi-, Gk. amphi- + râst "straight, direct, true;" from O.Pers. rāsta- "straight, true," rās- "to be right, straight, true;" Av. rāz- "to direct, put in line, set," razan- "order;" cf. Skt. raj- "to direct, stretch," rjuyant- "walking straight;" Gk. orektos "stretched out;" L. regere "to lead straight, guide, rule," p.p. rectus "right, straight;" Ger. recht; E. right; PIE base *reg- "move in a straight line," hence, "to direct, rule." right triangle   سه‌بر ِ راست   sebar-e râst (#)Fr.: triangle droit   A triangle one of whose angles is a → right angle.→ right; → triangle. right-hand rule   رزن ِ دست ِ راست   razan-e dast-e râstFr.: règle de la main droite   See → Fleming's rules.→ right; → hand; → rule. right-hand screw rule   رزن ِ پیچ ِ راست‌گرد   razan-e pic-e rast-gardFr.: règle de la vis droite   A rule that gives the direction of the resultant vector in a → vector product: A x B = C. It is the direction of advance of a right-hand screw whose axis, held perpendicular to the plane of A and B, is rotated in the same sense that rotates the first-named vector (A) into the second-named vector B through the smaller angle.→ right; → hand; → screw; → rule. right-handed   راستال، راستدست   râstâl, râstdast (#)Fr.: droitier   Using the right hand with greater skill or ease than the left.→ right; → hand + -ed.Râstâl, from râst, → right, + -al→ -al. Râstdast, with dast, → hand. rigid   سخت‌پای   saxtpây (#)Fr.: rigide   1) General: Stiff or unyielding; inflexible, strict, severe. 2) Physics: → rigid body; → rigidity.From L. rigidus "hard, stiff, rough," from rigere "to be stiff;" related to L. frigus "cold," Gk. rhigos "frost, cold."Saxtpây, from saxt, → hard, + pây present stem of pâyidan "to stand firm, to be constant, steady, fixed;" Mid.Pers. pâyitan, pâtan, pây- "to protect; wait, stand," Sogdian p'y "to protect, watch over;" O.Pers./Av. pâ(y)- "to protect, keep" pâtar- "protector, watcher," cf. Skt. pâ- "to protect, keep," pâti "protects;" Gk. poimen "shepherd," poma "lid, cover;" L. pastor "shepherd," panis "bread;" PIE base *pa- "to protect, guard, pasture, feed." rigid body   جسم ِ سخت‌پای   jesm-e saxtpâyFr.: corps rigide   Mechanics: A system of many particles whose positions relative to one another remain fixed.→ rigid; → body. rigidity   سخت‌پایی   saxtpâyiFr.: rigidité   1) The quality or state of being → rigid. See also → modulus of rigidity. 2) → magnetic rigidity.→ rigid + → -ity. Rigil Kentaurus (α Centauri)   پای ِ کنتاؤروس   pâ-ye KentâwrosFr.: Alpha du Centaure   Another name of → Alpha Centauri.Rigel, from Ar. rijl (رجل) "foot;" Kentaurus, → Centaurus.Pâ "foot, step" (from Mid.Pers. pâd, pây; Av. pad- "foot;" cf. Skt. pat; Gk. pos, genitive podos; L. pes, genitive pedis; P.Gmc. *fot; E. foot; Ger. Fuss; Fr. pied; PIE *pod-/*ped-); Kentâwros→ Centaurus.