niru-ye, bâzgardân, ~ bâzsâz
Fr.: force de rappel
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.
To hold back from action; keep in check; repress; to limit or hamper the activity, or effect of.
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.
restricted three-body problem
parâse-ye seh jesm-e forudâridé
Fr.: problème restreint à trois corps
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.
The act of restricting, the state or the condition of being restricted.
General: Something that happens as a consequence; outcome.
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.
šetâb-e barâyand (#)
Fr.: accélération résultante
An acceleration that results from the vector addition of two or more distinct accelerations.
niru-ye barâyand (#)
Fr.: force résultante
A single force which has the same effect as all other applied forces collectively.
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 kwer- "to do, to make").
The act of retarding or state of being retarded. → retardation plate.
Verbal noun of → retard.
Fr.: lame à retard
Same as → wave plate.
Fr.: champ retardé
The electric or magnetic field that is derived from the → retarded potentials.
Fr.: potentiel retardé
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.
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.
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").
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."
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.