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: 929
approximately
  نزدینانه   
nazdinâné

Fr.: approximativement   

Not exactly, but nearly or roughly.

Adverb of → approximate.

approximation
  نزدینش   
nazdineš

Fr.: approximation   

1) General: A guess or estimate; nearness in space, position, degree.
2) Math., Physics: Result that is not quite exact, but is within the limits of accuracy required for a given purpose.

Approximation, verbal noun of → approximate.

Nazdineš, verbal noun of nazdinidan, → approximate.

appulse
  همتاخت   
hamtâxt

Fr.:   

A situation in which two heavenly bodies apparently approach each other. A close → conjunction in which no → occultation actually occurs.

L. appulsus, from appellere, appulsum "to drive to," from ad, → ad- + pellere "to drive".

Hamtâxt from ham- "against; together" + tâxt, from tâxtan "to rush upon, run, assault".

apsidal
  هباکی   
habâki

Fr.: absidial   

Relating to an → apsis.

apsis; → -al.

apsidal motion
  جنبش ِ هباکی   
jonbeš-e habâki

Fr.: mouvement apsidial   

Rotation of the → line of apsides in the plane of the orbit in the same direction as the → revolution of the → secondary body. The major axis of the Earth's orbit rotates by 11.6 arcseconds per year.

apsidal; → motion.

apsidal precession
  پیشایانِ هباکی   
pišâyân-e habâki

Fr.: précession absidiale   

advance of perihelion, → relativistic precession.

apsidal; → precession.

apsides, line of
  خط ِ هباک‌ها   
xatt-e habâkhâ

Fr.: ligne des apsides   

The line connecting the two apsides, i.e. the major axis of an elliptical orbit. → apsis.

Apsides, pl. of → apside; → line.

apsis (pl. apsides)
  هباک   
habâk

Fr.: apside   

The point of greatest or least distance of the orbit of a celestial body from a center of attraction. The closest point is the → periapsis, the further point the → apoapsis.

L. apsis "arch, vault," from Gk. hapsis "loop, arch," from haptein "fasten together".

Mod.Pers. habâk "top of the head; the summit of a mountain".

apt
  نیاو   
niyâv

Fr.: approprié   

Exactly suitable; appropriate; suited to a purpose.

M.E., from L. aptus "fitted, suitable, fastened," from p.p. of *apere "to fasten;" akin to Hittite hap- "to attach;" PIE *ap- "to grasp, take, reach".

Niyâw "apt, suitable, appropriate," from Mid.Pers.

Apus
  مرغ ِ بهشتی   
Morq-e behešti (#)

Fr.: Oiseau de paradis   

The Bird of Paradise. A constellation in the southern hemisphere, at R.A. = 16 h, Dec. = -75°. Abbreviation: Aps; genitive form: Apodis.

L. apus "a kind of swallow," from Gk. apous "without feet, sand martin," from → a- "without" + pous "foot".

Morq-e behešti "bird of paradise," from morq "bird" + behešt "paradise".

Aquarids
  آبکشیان   
Âbkašiyân

Fr.: Aquarides   

Several → meteor showers that have their → radiants in the constellation → Aquarius. The main showers are:
1) Eta Aquarids, which occurs early in May and is apparently associated with → Halley's comet, and
2) Delta Aquarids occurring in early August.

Aquarids, from → Aquarius constellation + → -ids suffix denoting "descendant of, belonging to the family of."

Âbkašiyân, from Âbkaš + -iyân, → -ids.

Aquarius
  آبکش، ریزنده‌ی ِ آب   
Âbkeš, Rizande-ye âb (#)

Fr.: Verseau   

The Water Bearer. An extended southern constellation composed of rather faint stars (R.A. about 23h, Dec. about -15 deg). One of the signs of the → Zodiac, it is surrounded by → Pegasus, → Equuleus, and → Delphinus to the north, → Aquila to the west, → Pisces Austrinus and → Sculptor to the south, and → Cetus to the east. Abbreviation: Aqr, genitive from: Aquarii.

Aquarius, L. "water carrier," literally "of the water," translation of Gk. Hydrokhoos "the water-pourer," old Gk. name of this constellation.

Âbkeš "water carrier or drawer," from âb "water" (Mid.Pers. âb "water;" O. Pers. ap- "water;" Av. ap- "water;" cf. Skt. áp- "water;" Hitt. happa- "water;" PIE āp-, ab- "water, river;" cf. Gk. Apidanos, proper noun, a river in Thessalia; L. amnis "stream, river" (from *abnis); O.Ir. ab "river;" O.Prus. ape "stream;" Lith. upé "stream;" Latv. upe "brook") + keš "drawer," contraction of kešandé, from kešidan/kašidan "to carry, draw, extract, trail, drag" (Mid.Pers. kešidan "to draw, pull;" Av. karš- "to draw; to plough," karša- "furrow;" cf. Skt. kars-, kársati "to pull, drag, plough," Gk. pelo, pelomai "to be busy, to bustle;" PIE base kwels- "to plow").

Aquila
  شاهین   
Šâhin (#)

Fr.: Aigle   

The Eagle. A constellation on the celestial equator representing an eagle (R.A. about 19h30, Dec. about +5 deg). It is marked by the bright star → Altair (α Aquilae). Abbreviation: Aql, genitive form: Aquilae.

L. aquila "black eagle," fem. of aquilus "dark colored" (bird).

Šâhin "eagle," Av. saêna- "eagle," Skt. śyená- "eagle, falcon, hawk".

Aquila Rift
  چاک ِ شاهین   
câk-e Šâhin

Fr.: Rift de l'Aigle   

A long, dark structure located close to the → Galactic plane and occupying an area between longitudes l ~15° and ~35° and latitudes b ± 10° in the constellations Aquila, Serpens, and eastern Ophiuchus. The Aquila Rift is a complex of dust and → molecular clouds making part of → Gould's Belt in the → Orion Arm. The mass of the molecular gas, derived from → carbon monoxide (CO) observations (Dame et al. 2001, ApJ 547, 792), is in the range ~ 1-3 x 105 → solar masses. A distance of ~260 pc has been estimated for the Aquila Rift, but it is uncertain. Recent Herschel observations have revealed a filamentary structure in the Aquila Rift and the presence of a population of → pre-stellar cores as well as → young stellar objects (André et al. 2010, A&A 518, L102; Bontemps et al. 2010, A&A 518, L85; Könyves et al. 2010, A&A 518, L106).

Aquila; → rift.

Ara
  آتشدان   
Âtašdân (#)

Fr.: Autel   

L. ara "fire altar," from PIE as- "to burn".

Âtašdân "a hearth, a fire-place; a movable coal grate," from âtaš "fire" (from Mid.Pers. âtaxš, âzar-, O.Pers. *âtar-, Av. âtar-, from Indo-Iranian *âtar-, compare with L. âter (feminine âtra) "black" (from "blackened by fire"); PIE *âter) + -dân suffix denoting recipient.

Arabic astronomy
  اخترشناسی ِ عربی   
axtaršenâsi-ye Arabi (#)

Fr.: astronomie arabe   

The astronomical activities that took place from the 8th to the 14th century in the Middle East, Central Asia, North Africa, and Moorish Spain. Arab/Arabic is not meant as an ethnic but rather a linguistic term. In fact a large number of Non-Arab scholars, mainly Persians, Mongols, and Spanish people, wrote their works in Arabic. Even so, many astronomical works were also produced in the other languages of this civilization, especially Persian and in the later centuries Turkish. For example, the main → zijs were originally written in Persian, a notable example being the Zij of Ulugh Beg (c. A.D. 1394-1449), a landmark in precise observations before the Renaissance. Therefore, the term Arabic astronomy is misleading. It also creates a disparity with respect to Western scholars who wrote in Latin. The term "Latin astronomy" is meaningless and as far as these scholars are concerned, the Latin adjective is not specified. For example, the expressions like "the Latin astronomer Copernicus," "the Latin physicist Newton," or "the Latin philosopher Leibniz" are not used. See also → Islamic astronomy.

M.E. arabik, from O.Fr. arabique, from L. Arabicus; → astronomy.

Arago point
  نقطه‌ی ِ آراگو   
noqte-ye Arago

Fr.: point d'Arago   

A → neutral point located at about 20° above the → antisolar point.

Named for François Arago (1786-1853), French physicist; → point

arbitrary
  کامسر   
kâmsar

Fr.: arbitraire   

1) Based on individual will or choice rather than by reason or necessity.
2) Math.: Undetermined; of unspecified value. → arbitrary constant.

M.E., from O.Fr. arbitraire or directly from L. arbitrarius "depending on the will, uncertain," from → ad- "to" + baetere "to come, go."

Kâmsar, literally "at one's will," from kâm "desire, wish; cause, reason," → despite, + sar "person, individual," originally "→ head."

arbitrary constant
  پایای ِ کامسر   
pâyâ-ye kâmsar

Fr.: constante arbitraire   

A constant quantity in → equations which takes various values but which remains unaffected by the changes in the values of the → variables of the equation. Most → differential equations have more than one → solution. In general, the number of arbitrary constants of an ordinary differential equation is given by the → order of the highest → derivative.

arbitrary; → constant.

arborescence
  شاکه‌داری   
šâkedâri

Fr.: arborescence   

1) In → graph theory, a → rooted tree that has a natural orientation in which all → paths are directed away from the → root. More specifically, a → directed graph in which, for a → vertex u, called the → root, and any other vertex v, there is exactly one → directed path from u to v.
2) Biology: The state of being branched, or treelike, in structure, appearance, growth, or other properties.

From Fr. arborescence, from → arborescent + → -ance.

Šâkedâri, nous from šâkedâr, → arborescent.

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