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: 705
retarded wave
  موج ِ دیررس   
mowj-e dirras

Fr.: onde retardée   

An ordinary electromagnetic wave that goes forward with time. → Maxwell's equations are indifferent to the distinction between past and future. It is therefore permissible for the electromagnetic waves to go backward in time. Forward-in-time waves are called retarded, as they arrive after they are sent by the transmitter. Backward-in-time waves are called → advanced wave.

Retarded, adj. of → retard; → wavel.

rete
  تنندو، عنکبوت   
tanandu, ankabut

Fr.: araignée   

The component of a → planispheric astrolabe that is held against the → tympanum by the → horse, but can rotate freely in the → mater around the → pin to simulate the daily movement of the stars in the sky. It is the most characteristic part of the planispheric astrolabe.

From L. rete "net."

Tanandu "spider," from tanidan "to spin," → tension; ankabut "spider," loan from Arab.

reticle
  تاربست   
târbast (#)

Fr.: réticule   

A system of intersecting lines which are placed in the focus of the objective of an optical instrument to aid in sighting; aligning, or measuring. Same as reticule.

From L. reticulum "little net," from to ret(e) "net" + -i- + -culum variant of → -ula.

Târbast, from 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") + bast "joined, tied," past stem of bastan, vastan "to bind, shut" (O.Pers./Av. band- "to bind, fetter," banda- "band, tie" (cf. Skt. bandh- "to bind, tie, fasten;" PIE *bhendh- "to bind;" Ger. binden; E. bind).

Reticulum
  تور   
Tur (#)

Fr.: Réticule   

The Net. A small constellation in the southern hemisphere, at 4h right ascension, 62° south declination. It is centred on a group of stars with magnitudes 3.4 to 5 just north-west of the → Large Magellanic Cloud, and about halfway between → Canopus and → Achernar. Abbreviation: Ret; genitive: Reticuli.

L. reticulum "little net," named in 1752 by Abbé Nicolas Louis de Lacaille (1713-1762) to commemorate the reticle, an instrument he used to measure star positions. The constellation was first published by Isaak Habrecht of Strasbourg as the Rhombus, but was renamed by Lacaille as Reticulum Rhomboidalis.

Tur "net, fishing net, snare," related to târ "thread, warp, string," 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").

retina
  شبکیه   
šabakiyé (#)

Fr.: rétine   

The multi-layered, light-sensitive membrane lining the inside of the posterior wall of the eyeball. It contains the rods and cones that receive an image from the lens and send it to the brain through the optic nerve.

M.L. retina, from L. rete "net," Gerard of Cremona's 12c. translation of Arabic (tabaqa) shabakiyya "net-like (layer)," itself a translation of Gk. amphiblestron used by the famous Greek physician, surgeon, and philosopher Galen (AD c129-c216). This term had two meanings, "a surrounding coat" (of the vitreous) and "a fisherman's net." Galen used the word in the first sense, but when it was translated into Ar. the translator inappropriately chose the second meaning.

Šabakiyé, from Ar. šabakiya, from šabaka, šabakat "a net."

retired galaxy
  کهکشان ِ بازنشسته   
kahkešân-e bâznešasté

Fr.: galaxie retraitée   

An old galaxy with faint emission lines whose ratios are similar to those of → LINERs, i.e. galaxies with low-ionization nuclear emission-line regions. All galaxies after consuming their → molecular clouds, where stars are formed, follow a "passive" evolution during which their → stellar populations simply get older and older. The old stellar populations contain hot post-→ AGB stars and → white dwarfs which are able to ionize the surrounding gas and produce spectra identical to those of LINERS.

Retired in the sense "withdrawn from or no longer occupied with one's business or profession," p.p. of retire, from M.Fr. retirer "to withdraw (something)," from → re- "back" + O.Fr. tirer "to draw;" → galaxy. The concept of retired galaxies was first proposed by G. Stasińska et al. (2008, MNRAS 391, L29) to name the final stages of galaxies that cease their star forming activity. The word "retired" is also to be taken by opposition to "active" in the sense of "containing an accreting black hole" (like Seyfert galaxies), since liners are often thought to be a scaled down version of Seyfert nuclei.

Bâznešasté "retired," literally "seated back, seated away," from bâz-re- + nešasté "seated," p.p. of nešastan "to sit;" Mid.Pers. nišastan "to sit;" O.Pers. nišādayam [1 sg.impf.caus.act.] "to sit down, to establish," hadiš- "abode;" Av. nišasiiā [1 sg.subj.acr.] "I shall sit down," from nihad- "to sit down," from ni- "down, in, into," → ni-, + had- "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.

retreat
  ۱) پس‌کشید؛ ۲) پس‌کشیدن   
1) pas-kešid; 2) pas-kešidan

Fr.: 1) retrait; 2) battre en retraite   

1a) The forced or strategic withdrawal of an army or an armed force before an enemy, or the withdrawing of a naval force from action.
1b) The act of withdrawing, as into safety or privacy; retirement; seclusion.
2) To withdraw, retire, or draw back, especially for shelter or seclusion.

Mi.E. retret, from O.Fr., variant of retrait, noun use of p.p. of retraire "to draw back," from L. retrahere, from → re- + trahere "to draw."

Pas-kešidan "to retreat, pull back," from pas, → back, + kašidan "to pull, to draw, to drag," → galaxy.

retrograde
  پسرو، پسرفت   
pasrow (#), pasraft (#)

Fr.: rétrograde   

Moving backward; having a backward motion or direction. → retrograde motion.

M.E., from L. retrogradus "going backward," from retrogradi "move backward," from retro- "backward" + gradi "to go, step."

Pasrow, pasraft, from pas- "back, behind," → back, + row, raft present and past stems of raftan "to go, walk;" (Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").

retrograde motion
  جنبش ِ پسرو   
jonbeš-e pasrow

Fr.: mouvement rétrograde   

The orbital motion or rotation of a solar system body in a clockwise direction (East to West) when viewed from the north pole of the ecliptic. It is a motion opposed to the → direct motion of the great majority of solar system bodies.

retrograde; → motion.

retrograde object
  بر‌آخت ِ پسرو   
barâxt-e pasrow

Fr.: objet rétrograde   

An object which has a retrograde orbit around its primary.

retrograde; → object.

retrograde orbit
  مدار ِ پسرفت   
madâr-e pasraft

Fr.: orbite rétrograde   

An orbit with an inclination between 90° and 270° such as those of some comets and small asteroids orbiting the Sun.

retrograde; → orbit.

Reuleaux triangle
  سه‌بر ِ رولو   
sebar-e Reuleaux

Fr.: triangle de Reuleaux   

A shape of constant width created using an equilateral triangle and three similar circles. The equilateral triangle lies in the first circle with a vertex coinciding with the center of the circle and the sides equal to the circle radius. The centers of the two other circles are located at the two other vertices. The Reuleaux triangle is the intersection of the three circles.

Named after Franz Reuleaux (1829-1905), a German engineer, specialist of analysis and design of mechines; → triangle.

reversal
  وارونش، واگردانی   
vâruneš, vâgardâni

Fr.: inversion, interversion   

An act or instance of reversing. The state of being reversed. → phase reversal.

From → reverse + → -al.

reverse
  وارون، واگرد   
vârun, vâgard (#)

Fr.: contraire, opposé   

Opposite or contrary in position, direction, order, etc.
Acting in a manner opposite or contrary to that which is usual. → invert = vârun (وارون).

M.E. revers from O.Fr. revers "reverse, cross," from L. reversus, p.p. of revertere "to turn back," from → re- "back" + vertere "to turn," cognate with Pers. gard "to turn," as below.

Vârun "inverse, upside down," from vâ- "back, backward, again, re-," variant of bâz-, from Mid.Pers. abâz-, apâc-, O.Pers. apa- [pref.] "away, from;" Av. apa- [pref.] "away, from," apaš [adv.] "toward the back;" cf. Skt. ápāñc "situated behind."
Vâgard, from vâ-, → re-, + gard present stem of gardidan, gaštan "to turn, to change" (Mid.Pers. vartitan; Av. varət- "to turn, revolve;" cf. Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend").

reverse shock
  تش ِ واگرد   
toš-e vâgard

Fr.: choc en retour   

A → shock front in a → supernova remnant (SNR) arising from the interaction of the → supersonic  → forward shock wave with the → interstellar medium (ISM) material. The reverse shock forms as the high pressure gas behind the forward shock wave expands and pushes back on the stellar ejecta. Reverse shock propagates into ejecta, starting from outside.

reverse; → shock.

reversible
  واگشت‌پذیر   
vâgaštpazir (#)

Fr.: réversible   

Capable of returning to an original condition. → reversible process.

reverse + → -able.

reversible process
  فراروند ِ واگشت‌پذیر   
farâravand-e vâgaštpazir (#)

Fr.: processus réversible   

Any physical process which can be performed in the reverse direction, the whole series of changes constituting the process being exactly reversed. → irreversible process.

reversible; → process.

reversing layer
  لایه‌ی ِ واگردان   
lâye-ye vâgardân (#)

Fr.: couche d'inversion   

A layer of relatively cool gas forming the lower part of the Sun's chromosphere, just above the photosphere, that gives rise to absorption lines in the Sun's spectrum.

Reversing verbal adj. of → reverse; → layer.

review
  ۱) بازدا؛ ۲) بازدا کردن   
1) bâzdâ; 2) bâzdâ kardan

Fr.: 1) revue; 2) faire une revue   

1a) A critical article or report.
1b) The process of going over a subject again in study in order to examine and summarize the facts.
2) To discuss a research subject in a critical review; write a critical report upon.

M.E., from O.Fr. reveue "a reviewing, review," from feminine p.p. of revoir "to see again, reexamine," from O.Fr. reveoir, from → re- + veoir, veeir "to see."

Bâzdâ, from bâz-, → re-, + root of didan "to see" (Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Av. dā(y)- "to see," didāti "sees;" cf. Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen") + kardan "to do," → -or.

review talk
  سخنرانی ِ بازدایی   
soxanrâni-ye bâzdâyi

Fr.: papier de revue   

A talk that deals with a subject by examining, criticizing, and summarizing the facts.

review; → talk.

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