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

1) To bring back into existence, use, or the like; reestablish.
2) To bring back to a former, original, or normal condition, as a building, statue, or painting (Dictionary.com).

M.E., from O.Fr. restorer, from L. restaurare "repair, rebuild, renew," from → re- "back, again" + -staurare, from PIE root *sta- "to stand, set down, make or be firm," → state.

Bâzsâxtan, from bâz- "back, again," → re-, + sâxtan "to build, make, fashion; to adapt, adjust, be fit" (from Mid.Pers. sâxtan, sâz-, Manichean Parthian s'c'dn "to prepare, to form;" Av. sak- "to understand, to mark," sâcaya- (causative) "to teach").
Bâzgardândan, from bâz-+ gardândan "to turn (around)," accusative of gardidan, gaštan "to change, to turn, → revolve."

An image that has been upgraded by a process of → image restoration.

Restored, p;p. of restore, → restoration; → image.

Tasvir, → image; bâzsâxté, p.p. of bâzsâxtan, → restoration.

A force that comes into play after a system is perturbed away from the equilibrium, tending to bring the system back the equilibrium position. For example, when a pendulum is displaced from its equilibrium position, it is subject to a restoring force due to gravity that will accelerate it back toward the equilibrium position. The restoring force combined with the pendulum's mass causes it to oscillate about the equilibrium position.

→ restore; → force.

To hold back from action; keep in check; repress; to limit or hamper the activity, or effect of.

M.E. restreynen, from O.Fr. restreindre "press, push together; curb, bridle;" from L. restringere "to draw back tightly, confine," from → re- "back" + stringere "draw tight," → strain.

Bâzdâštan, from bâz- prefix denoting "reversal, opposition," → re-, + dâštan "to hold," → property.

To confine or keep within limits. → restricted three-body problem.

From L. restrictus, p.p. of restringere "to restrict, bind fast, restrain," from → re- "back" + stringere "to draw tight."

Forudâštan "to keep down, hold under control, bring to a halt" (Steingass, Dehxodâ), from foru- "down, downward," → de-, + dâšt past stem of dâštan "to have, to possess" (Mid.Pers. dâštan; O.Pers./Av. root dar- "to hold, keep back, maintain, keep in mind;" cf. Skt. dhr-, dharma- "law;" Gk. thronos "elevated seat, throne;" L. firmus "firm, stable;" Lith. daryti "to make;" PIE *dher- "to hold, support") + -an infinitive suffix.
Forudâridan, from foru- + dâr present stem of dâštan + -idan

A special case of the → three-body problem in which the → mass of one of the bodies is negligible compared to that of the two others. If the relative motion of the two massive components is a circle, the situation is referred to as the → circular restricted three-body problem. An example would be a space probe moving in the → gravitational fields of the → Earth and the → Moon, which revolve very nearly in circles about their common → center of mass.

→ restrict; → three; → body; → problem.

The act of restricting, the state or the condition of being restricted.

Verbal noun, → restrict + → -tion.

General: Something that happens as a consequence; outcome.
Math.: A quantity, expression, etc., obtained by calculation. → resultant.

M.E. resulten (v.); L. resultare "to result," in classical L. "to spring forward, rebound," frequentative of p.p. of resilire "to rebound," from re- "back" + salire "to jump, leap."

Barâyé, literally "upcoming," from bar- "on; up; upon; in; into; at; forth; with; near; before; according to" (Mid.Pers. abar; O.Pers. upariy "above; over, upon, according to;" Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over") + ây- present stem of âmadan "to come, arrive, become" (Av. ay- "to go, to come," aēiti "goes;" O.Pers. aitiy "goes;" Skt. e- "to come near," eti "arrival;" L. ire "to go;" Goth. iddja "went," Lith. eiti "to go;" Rus. idti "to go") + -e nuance suffix.

Physics: The single vector obtained by applying vector addition to two or more given vectors.

M.E., n. use of L. resultant-, pr.p. of resultare, → result.

Barâyand, from bar, → result, + -âyand short for âyandé agent noun of âmadan "to come, arrive, become," → result.

An acceleration that results from the vector addition of two or more distinct accelerations.

→ resultant; → acceleration.

A single force which has the same effect as all other applied forces collectively.

→ resultant; → force.

A slowing down, holding back, or hindrance,

M.E., from M.Fr., from L retardare "to make slow, delay, keep back, hinder," from → re-, intensive prefix, + tardare "to slow."

Dirkard "delay," from dir "slowly, tardily; late" (Mid.Pers. dêr, variants dagr, drâz "long;" (Mod.Pers. derâz "long," variant Laki, Kurdi derež); O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "long (in space and time);" L. longus "long;" Gk. dolikhos "elongated;" O.H.G., Ger. lang; Goth. laggs "long;" PIE base *dlonghos- "long") + kard past stem of kardan "to do, to make" (kâr "work," varaint kar (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build;" Av. kərənaoiti "he makes;" cf. Skt. kr- "to do, to make," krnoti "he makes, he does," karoti "he makes, he does," karma "act, deed;" PIE base k^wer- "to do, to make").

The act of retarding or state of being retarded. → retardation plate.

Verbal noun of → retard.

Same as → wave plate.

→ retardation; → plate.

The electric or magnetic field that is derived from the → retarded potentials.

Retarded, adj. of → retard; → field.

The → electromagnetic potential at an instant in time and a point in space as a function of the charges and currents that existed at earlier times.

Retarded, adj. of → retard; → potential.

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.

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.

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).

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").