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

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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 identity axiom   بنداشت ِ ایدانی   bondâšt-e idâniFr.: axiome d'identité   A basic rule in → group theory stating that there exists a unit group element e, called the identity, such that for any element a of the group a * e = e * a = a.→ identity; → axiom. identity element   بن‌پار ِ ایدانی   bonpâr-e idâniFr.: élément neutre   In a mathematical system, an element which leaves unchanged any other element on which it operates. Thus 0 is the identity element for addition: a + 0 = a. And 1 is the identity element for multiplication: a . 1 = a.→ identity; → element. identity function   کریای ِ ایدانی   karyâ-ye idâniFr.: fonction d'identité   Math.: Any function f for which f(x) = x for all x in the domain of definition.→ identity; → function. identity matrix   ماتریس ِ ایدانی   mâtris-e idâniFr.: matrice identité   In linear algebra, the simplest nontrivial diagonal matrix, an n-by-n square matrix with ones on the main diagonal and zeros elsewhere.→ identity; → matrix. identity operator   آپارگر ِ ایدانی   âpârgar-e idâniFr.: opérateur d'identité   An operator which takes a real number to the same real number.→ identity; → operator. if   اگر   agar (#)Fr.: si   (Conjunction) in case that; granting or supposing that; on condition that. → if and only if.M.E., from O.E. gif; akin to O.H.G. ibu "if."Agar "if," from Mid.Pers. agar, hakar "if;" O.Pers. ha-karam "once;" from ha- "one," variant ham-, → com- (cf. Av. ha-; Skt. sa-; Gk. ha-; L. sem-; PIE *sem- "one"), + karam- "a time," maybe from kar- "to do; doing," → work; cf. Av. hakərət "once;" Skt. sakrt "once;" Gk. hapaks "once;" L. semel "once." if and only if (iff)   اگر و ایواز اگر، ~ ~ تنها ~   agar va ivâz agar, ~ ~ tanhâ ~Fr.: si et seulement si   Logic, Math.: An → expression indicating that two → statements so connected are → necessary and sufficient conditions for one another. The corresponding logical symbols usually used are: ↔, ⇔, ≡, and iff.→ if; → and; → only. igneous rock   سنگ ِ آذرین   sang-e âzarin (#)Fr.: roche ignée   A → rock formed by the solidification of molten material that originated within the Earth (as → magma or → lava).Igneous, from L. igneus "of fire, fiery," from ignis "fire," from PIE *egni- (cf. Skt. agni- "fire, sacrificial fire," O.C.S. ogni, Lith. ugnis "fire"); → rock.Sang "stone, rock," → stone; âzarin "fiery," from âzar, variants âtaš, taš, from Mid.Pers. âtaxš, âtur "fire;" Av. ātar-, āθr- "fire," singular nominative ātarš-; O.Pers. ātar- "fire;" Av. āθaurvan- "fire priest;" Skt. átharvan- "fire priest;" cf. L. ater "black" ("blackened by fire"); Arm. airem "burns;" Serb. vatra "fire;" PIE base *āter- "fire" + -in adj. suffix. ignite   ۱) گیراندن؛ ۲) گرفتن   1) girândan; 2) gereftan (#)Fr.: 1) enflammer, allumer; 2) s'enflammer, s'allumer   1) To set on fire. 2) To take fire, to begin to burn.From L. ignitus, p.p. of ignire "to set fire," from ignis "fire, flame, light."Girândan transitive form of gereftan "to take, catch" (Mid.Pers. griftan, Av./O.Pers. grab- "to take, seize," cf. Skt. grah-, grabh- "to seize, take," graha "seizing, holding, perceiving," M.L.G. grabben "to grab," from P.Gmc. *grab, E. grab "to take or grasp suddenly;" PIE base *ghrebh- "to seize"). ignition   گیرانش؛ گیرش   girâneš; gireš (#)Fr.: inflammation, allumage   1) The act or fact of igniting; state of being ignited. 2) The process of setting something on fire.Verbal noun of → ignite. ignition temperature   دمای ِ گیرانش   damâ-ye girânešFr.: température d'inflammation   The minimum temperature to which a fuel must be heated in order to initiate self sustained combustion independent of another heat source.→ ignition; → temperature. ignorable coordinate   همارای ِ نادیده‌انگاشته   hamârâ-ye nâdidé engâshtéFr.: coordonnée ignorée   A → generalized coordinate that does not appear explicitly in the → Lagrangian function. Also called → cyclic coordinate. Ignorable coordinates do not participate in the → Legendre transformation, and are also absent from the → Hamiltonian function. The generalized → momentum associated with an ignorable coordinate is a → constant of the motion.→ ignore; → coordinate. ignore   نادیده‌انگاشتن   nâdidé engâštan (#)Fr.: ignorer, négliger   To set aside, e.g. → ignorable coordinate.From Fr. ignorer, from L. ignorare "not to know, disregard," from ignarus "not knowing, unaware," from in- "not," → un-, + gnarus "aware, acquainted with," related to gnoscere "to → know".Nâdidé engâštan literally "supposed not seen," from nâdidé "not seen" (from nâ- "not," → un- + didé "seen," p.p. of didan "to see," → sight) + engâštan "to suppose" (→ hypothesis). illuminance   روشنایی، تنویی ِ ~   rowšanâyi, tanuyi-ye ~Fr.: éclairement lumineux   Optics: Intensity of → illumination. The amount of visible light incident per unit area of surface per second; measured in lux (lumens per unit square meter). → irradiance.Rowšanâyi, → illumination; tanuyi→ intensity. illumination   روشنایی   rowšanâyi (#)Fr.: éclairement, illumination   General: An act or instance of illuminating. The fact or condition of being illuminated.Illumination, from O.Fr. illumination, from L. illuminationem (nom. illuminatio), from illuminare "to throw into light," from → in- "in" + lumen "light," cognate with Pers. rowšan, as below.Rowšanâyi, noun of quality and state from rowšan "bright, clear," related to ruz "day," foruq "light," and afruxtan "to light, kindle," rowzané "window, aperture;" Mid.Pers. rôšn "light; bright, luminous," rôc "day," rocânak "window;" O.Pers. raucah-, Av. raocana- "bright, shining, radiant," raocah- "light, luminous; daylight;" akin to Skt. rocaná- "bright, shining," roka- "brightness, light;" Gk. leukos "white, clear;" L. lux "light," also lumen "light, window," luna "Moon;" E. light; Ger. Licht; Fr. lumière; PIE base *leuk- "light, brightness." illusion   سفمان   safmân (#)Fr.: illusion   1) A false sense impression of something actually present. 2) Something that produces a false or misleading impression of reality. → optical illusion. 3) An instance of being deceived.From O.Fr. illusion "a mocking," from L. illusionem (nom. illusio) "a mocking, irony," from illudere "to mock at," literally "to play with," from in- "at" + ludere "to play," from ludus "a game, play;" PIE base *leid- "to play, jest."Safmân, literally "wrong thought, ~ idea," from saf "wrong" (Tâleši), → false, + mân "thought," → idea. image   ۱) وینه، تصویر؛ ۲) وینه گرفتن، ~ برداشتن   1) vine, tasvir (#); 2) vine gereftan, ~ bardâštanFr.: image   1) In an optical system, the point to which light rays are converged (real image) or from which they appear to diverge (virtual image) after reflection or refraction. Math.: A number, point, or unique element of a space that corresponds to some other number, point, or unit element. 2) To make an image of; to picture or represent in the mind.From O.Fr. image, from L. imaginem (nom. imago) "copy, picture, likeness " from stem of imitari "to copy, imitate," from im-, stem of imitare "to copy, imitate" + -ago noun suffix.1) Vine, from (Sorani) Kurd. vina or vena "image, picture; similar," from vin/ven, variant of bin, present stem of dîtin, Pers. didan "to see, to look;" cf. Taleshi vinde "to see," Tati vindiyan "to see," Persian bin-, didan "→ see." The relation between "image" and "see" is probably from the fact that the image of a subject can be seen without its presence. Tasvir, loan from Ar. 2) Infinitive with gereftan "take," → take, and dâštan "to have, to hold," → property. image co-adding   هم‌افزایش ِ وینه‌ها، ~ تصویرها   hamafzâyeš-e vinehâ, ~ tasvirhâFr.: addition d'images   The process of adding several usually low-exposure images to create an image having a significantly higher signal/noise ratio.→ image; → co-; → add. image deblurring   تیگش ِ وینه، ~ تصویر   tigeš-e vine, ~ tasvirFr.: correction de l'image brouillée   A technique using a mathematical model of the blurring process to recover the original, sharp image. See also → blurred image.→ image; → deburring. image formation   دیسش ِ وینه، ~ تصویر   diseš-e vine, ~ tasvirFr.: formation de l'image   The meeting of light rays emanating from an object after crossing an optical system.→ image; → formation.