An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -ab aba abs abs abs acc acc act act ada adi adv afo agi Ale alg Alk Aln alr alt amb ana And ang ani ano ant ant ape apo app aps arc arg Aro asc ass ast ast asy atm att aur ave axi > >>

Number of Results: 888
miyângin (#)

Fr.: moyenne   

A number representing a group of quantities, obtained by adding each quantity of the group and dividing the total by the number of quantities. Same as → arithmetic mean.

From O.Fr. avarie "damage to ship," from It. avaria or maybe avere, O.Fr. aveir "property, goods," from L. habere "to have." Meaning shifted to "equal sharing of such loss by the interested parties."

Miyângin "the middle; middle-sized; the middle pearl in a string," from miyân, → middle, + -gin a suffix forming adjectives of possession.

average velocity
  تندای ِ میانگین   
tondâ-ye miyângin

Fr.: vitesse moyenne   

The ratio of the displacement (Δx) of a particle, as it moves from point A to point B, to the corresponding time interval: v = Δx/Δt.

average; → velocity.

averted vision
  نگاه ِ کژ   
negâh-e kaž (#)

Fr.: regard oblique   

The technique of looking slightly to the side of a faint object being studied while continuing to concentrate on the object. The technique helps bring out details which otherwise would be missed by looking directly at an object. The reason is that the portion of the eye's retina that best detects dim light (fovea) is located all around the edges rather than the center.

Averted p.p. from avert, from O.Fr. avertir, from L. avertere "to turn away," from → ab- "from, away" + vertere "to turn" (cognate with Pers. gardidan "to turn"); → vision.

Negâh, → vision; kaž "averted."

Avogadro's law
  قانون ِ آووگادرو   
qânun-e Avogâdro (#)

Fr.: loi d'Avogadro   

A statement according to which equal volumes of different gases contain an equal number of molecules under the same conditions of temperature and pressure.

After Amedeo Avogadro (1776-1856), Italian chemist and physicist, who advanced the hypothesis in 1811.

Avogadro's number
  عدد ِ آووگادرو   
adad-e Avogâdro (#)

Fr.: Nombre d'Avogadro   

The number of atoms in 12 grams of 12C; by extension, the number of atoms in a gram-atom (or the number of molecules in a → mole) of any substance: 6.02 × 1023.

Named after Amedeo Avogadro (1776-1856), whose law allowed other physicists to calculate Avogadro's number; → number.

âgâh (#)

Fr.: conscient   

Having knowledge; conscious; informed; alert. → awareness.

M.E., variant of iwar, O.E. gewær; cf. O.S. giwar, M.Du. gheware, O.H.G. giwar, Ger. gewahr.

Âgâh "aware, knowing," related to negâh "look, attention;" Mid.Pers. âkâh; Av. ākas- "to look;" Proto-Iranian *kas- "to look, appear;" cf. Skt. kāś- "to become visible, appear;" Gk. tekmar, tekmor "sign, mark;"

âgâhi (#)

Fr.: conscience   

The state or condition of being aware; having knowledge; consciousness (
See also: → Space Situational Awareness.

aware; → -ness.

âse-yi (#)

Fr.: axial   

Of, pertaining to, characterized by, or forming an axis.

axis; → -al.

axial inclination
  درکیل ِ آسه   
darkil-e âsé

Fr.: inclinaison de l'axe   

The angle at which a planet's axis of rotation is tilted, with respect to that of the planet's orbit.

axial; → inclination.

axial precession
  پیشایان ِ آسه‌ای   
pišâyân-e âse-yi

Fr.: précession axiale   

1) A change in the orientation of the → rotation axis of a non-spherical, spinning body caused by → gravity. A rotating top will precess in a direction determined by the → torque exerted by its → weight. The precession → angular velocity is inversely proportional to the spin angular velocity, so that the precession is faster and more pronounced as the top slows down.
2) In particular, the gradual shift in the orientation of Earth's rotation axis which traces out a conical path once every ~ 26,000 years. The cause of the Earth's precession is the → equatorial bulge of the Earth, brought about by the → centrifugal force of the → rotation, which has changed the Earth from a perfect sphere to a slightly flattened one, thicker across the equator. The attraction of the Moon and Sun on the bulge is the reason which makes the Earth precess.

axial; → precession.

axial symmetry
  همامونی ِ آسه‌ای   
hamâmuni-ye âse-yi

Fr.: symmétrie axiale   

A symmetry with respect to a line. A geometric configuration is said to have axial symmetry if it remains unchanged when rotated about a given line.

axial; → symmetry.

axial tilt
  گرای ِ آسه   
gerâ-ye âsé

Fr.: inclinaison de l'axe   

The angle between an object's → rotation axis and its → orbital axis. In other words, the angle between its → equatorial plane and → orbital plane. Same as → axial inclination and → obliquity, but not to be confounded with → orbital inclination.

axial; → tilt.

  بنداشت، ارز‌آغازه   
bondâšt (#), arzâqâzé (#)

Fr.: axiome   

In any system of mathematics or logic, a statement or proposition from which secondary statements or propositions are derived. The truth of an axiom is either taken for granted or assumed. In modern practice, axiom and → postulate have the same meaning.

M.Fr. axiome, from L. axioma, from Gk. axioma "authority," literally "something worthy," from axioun "to think worthy," from axios "worthy," from PIE adj. *ag-ty-o- "weighty," from base *ag- "to drive, draw, move."

Bondâšt, literally "taking as the base," from bon "root, origin, base" + dâšt "held," from dâštan "to have, to hold, to maintain, to consider."
Arzâqâzé, from arz "value" + âqâzé "beginning, principle," from âqâz "beginning."

axiom of constraints
  بنداشت ِ پاوندها   
bondâšt-e pâvandhâ

Fr.: axiome des contraintes   

An axiom in → statics, stating that any → constrained body can be treated as a → free body detached from its → constraints, provided the latter are represented by their → reactions.

axiom; → constraint.


Fr.: axiomatique   

Of, relating to, or resembling an → axiom.

axiom; → -ic.

axiomatic system
  راژمان ِ بنداشتی   
râžmân-e bondâšti

Fr.: système axiomatique   

Any system of → logic which explicitly states → axioms from which → theorems can be → deduced.

axiomatic; → system.

aksion (#)

Fr.: axion   

A hypothetical weakly-interacting → boson of small mass required by models of → particle physics in order to solve the strong CP problem and explain a number of observed astrophysical/cosmological phenomena, including → dark matter, and the dimming of → type Ia → supernovae (→ accelerating Universe). Photons traveling in the → intergalactic medium would in part turn into axions in the presence of magnetic fields. The transformed photons are not detected on Earth and therefore supernovae would appear fainter even if the Universe is not accelerating.

Axion, first coined by Frank Wilczek (2004 Nobel Prize in Physics) apparently after a brand of washing detergent! The reason seems to be the idea that the particle will iron out a wrinkle in the → standard model of fundamental particles and forces while solving the problem of the Universe's → missing mass.

âsé (#)

Fr.: axe   

1) One of the principal lines through the center of a figure or a solid, especially, the line which divides the figure or solid symmetrically.
2) A fixed line along which distances are measured or to which position are referred.

L. axis "axle, pivot," akin to O.E. eax "axis, axle," Gk. axon "axle," Skt. aksa- "axle, axis, beam of a balance;" PIE base *aks- "axis."

Âsé, from Pers. dialects: Qâyeni asak "the shaft connecting the plough to the yoke," Lori esi "a pillar (used to put up a tribal tent)," variants hosi, hosin, Tabari âssen "the foot of a door on which it turns," cf. Skt. ISA- "pole or shafts of a carriage or plough," Av. aêša "the two shafts," Mod.Pers. xiš "plough(share)," Gk. oiax "handle of rudder, tiller, helm," PIE base *ei-, *oi- "pole, thill."

axis of rotation
  آسه‌ی ِ چرخش   
âse-ye carxeš

Fr.: axe de rotation   

Same as → rotation axis and → rotational axis.

axis; → rotation.

  همامون ِ آسه‌ای، آسه-همامون   
hamâmun-e âse-yi, âse-hamâmun

Fr.: axisymétrique   

Having → axisymmetry.

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