O.Fr., from L. autumnus, a word probably of Etruscan origin.
Pâyiz, from Mid.Pers. pâdiz or pâtez, from Proto-Iranian *pâti-z(a)ya- "near winter," from pâti "near" + *z(a)ya- "winter," compare with Av. zyan- or zyam- "winter" (Skt. heman, Gk. xeimon, L. hiems).
Fr.: équinoxe d'automne
One of the two points where the → ecliptic crosses the → celestial equator. At the autumnal equinox the Sun appears to be moving across the equator from the northern celestial hemisphere to the southern celestial hemisphere. The instant of the event.
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.
Fr.: accélération moyenne
Of a body traveling from A to B, the change of → velocity divided by the time interval: ā = (v2 - v1) / (t2 - t1).
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.
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.
Negâh, → vision; kaž "averted."
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.
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.
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;"
The state or condition of being aware; having knowledge; consciousness
Of, pertaining to, characterized by, or forming an axis.
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.
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.
→ angular velocity is
inversely proportional to the spin angular velocity, so that the
precession is faster and more pronounced as the top slows down.
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.
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.
bondâšt (#), arzâqâzé (#)
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."
axiom of constraints
Fr.: axiome des contraintes
Of, relating to, or resembling an → axiom.
Fr.: système axiomatique
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.