<< < R A rad rad rad rad rad rad Ram Ran rat rea rea rec rec red red ref ref reg rei rel rel rem rep res res res res rev rhe Rie rig Rit roe Ros rot Ruh Ryd > >>
Riemann's geometry hendese-ye Riemann Fr.: géométrie de Riemann Same as → Riemannian geometry. → Riemannian; → geometry. |
Riemannian 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 hendese-ye Riemanni Fr.: 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 baslâ-ye Riemanni Fr.: 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 metrik-e Riemanni Fr.: métrique riemannienne A positive-definite inner product, (.,.)_{x}, on T_{x}(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 câk, gosal-darré Fr.: rift; fissure, crevasse 1) General: a gap or break made by splitting, cleaving, etc.; fissure; cleft. 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 gosal-darré Fr.: fossé d'effondrement, ~ tectonique A long, narrow valley formed by the lowering of land between two → faults. Also called → graben. |
Rigel (β Ori) 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' ( Rejl, from Ar., as above. |
Rigel Kentaurus Pâ-ye Kentawros Fr.: 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 1) râst (#); 2) dorost; 3) râšan Fr.: droit 1a) Straight, free from curves, angles, or irregularities.
→ right ascension. 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;" |
right angle zâviye-ye râst Fr.: angle droit An angle of 90°. |
right ascension 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 sebar-e râst (#) Fr.: triangle droit A triangle one of whose angles is a → right angle. |
right-hand rule razan-e dast-e râst Fr.: règle de la main droite See → Fleming's rules. |
right-hand screw rule razan-e pic-e rast-gard Fr.: 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-handed râstâl, râstdast (#) Fr.: droitier Using the right hand with greater skill or ease than the left. Râstâl, from râst, → right, + -al→ -al. Râstdast, with dast, → hand. |
rigid saxtpây (#) Fr.: rigide 1) General: Stiff or unyielding; inflexible, strict, severe. 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 jesm-e saxtpây Fr.: corps rigide Mechanics: A system of many particles whose positions relative to one another remain fixed. |
rigidity saxtpâyi Fr.: rigidité 1) The quality or state of being → rigid.
See also → modulus of rigidity. |
Rigil Kentaurus (α Centauri) pâ-ye Kentâwros Fr.: Alpha du Centaure Another name of → Alpha Centauri. Rigel, from Ar. rijl ( 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. |
<< < R A rad rad rad rad rad rad Ram Ran rat rea rea rec rec red red ref ref reg rei rel rel rem rep res res res res rev rhe Rie rig Rit roe Ros rot Ruh Ryd > >>