An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Of the → cosmic microwave background radiation, a plot of how much the temperature varies from point to point on the sky versus the angular frequency. This spectrum answers fundamental questions about the nature of the Universe. → cosmic microwave background anisotropy; → dipole anisotropy.

→ angular; → power; → spectrum.

Of a telescope, the smallest angle betwwen two → point sources that produces distinct images. It depends on both the wavelength at which observations are made and on the diameter of the telescope. Same as → spatial resolution.

→ angular; → resolution.

Same as → angular distance.

→ angular; → separation.

Same as → angular diameter distance.

→ angular; → size; → distance.

A measure of the angular displacement per unit time. Of a particle traveling on a circular path or a rotating body, the ratio of the angle traversed to the amount of time it takes to traverse that angle: ω = dθ/dt. For a rigid body, all lines in it rotate through the same angle in the same time, and the angular velocity is the characteristic of the body as a whole. The angular velocity is related to the linear velocity by the equation v = rω, where r is the distance of the point from the rotation axis. → vector angular velocity.

→ angular; → velocity.

Any living creature that is distinguished from plants by independent movement and responsive sense organs.

From L. animale "living being, being which breathes," neuter of animalis "animate, living; of the air," from anima "breath; soul; breeze," cognate with Pers. jân, as below.

Jânevar, jânvar, Mid.Pers. gyânwar "animal; animate," literally "living, alive; quick," from jân, Mid.Pers. (+ prefix *ui-) gyân "(breathing) soul," gyânig "spiritual, vital;" Av. viiānayā "spirit(ness)"; Proto-Iranian *HanH- "to breathe" cf. Skt. ani- "to breathe," aniti "breathes;" Gk. anemos "wind;" L. animus "soul, spirit," anima "breeze, breath, soul;" Goth. uz-anan "to exhale" (Cheung 2007) + -e epenthesis + -var possession suffix; also hen o hen "to pant;" dialects, e.g. Lori, Kurd., henâs, henâsa "breath," henowša "panting."

1) To give life to; make alive; make lively or vigorous; give motion to.
2) To give an image or cartoon character the appearance of movement using animation techniques.

From L. animatus p.p. of animare "give breath to," also "to endow with a particular spirit, to give courage to," from anima "life, breath"  L. animus "soul, spirit," anima "breeze, breath, soul;" Goth. uz-anan "to exhale;" Gk. anemos "wind;" PIE root *ane- "to blow, to breathe;" cognate with Pers. jân "vital spirit, soul, mind," as below.

Farhanidan, from far- perfection prefix + han variant of jân "vital spirit, soul;" hen o hen "to pant;" Lori, Kurd., henâs, henâsa "breath," henowša "panting;" Mid.Pers. (+ prefix *ui-) gyân "(breathing) soul," gyânig "spiritual, vital;" Av. viiānayā "spirit(ness);" Proto-Iranian *HanH- "to breathe" cf. Skt. ani- "to breathe," aniti "breathes;" Gk. and L., as above, + -idan infinitive suffix.

1) An act or instance of animating or enlivening; the state or condition of being animated.
2) The technique of imaging successive drawings or positions of cartoons to create an illusion of movement when the film is shown as a sequence.

→ animate; → -tion.

A → negatively charged → ion or → radical. Anions in a liquid subjected to electric potential are attracted toward the → anode. See also → cation.

From Gk. anienai "to go up," from an-, from → ana- "up," + -i-, from ire, eo "to go, walk," cf. Pers. ây-, → assembly, + -on, as in → ion.

In an imaging system, the dependence of its performance on field angle. In other words, the spatial variability of the → point spread function for off-axis sources.

→ an- + → isoplanatism.

The departure from → isoplanicity.

→ an-; → isoplanicity.

Describing a medium in which certain physical properties are different in different directions.

→ anisotropy; → -ic.

A solution to Einstein's theory of → general relativity that is spatially homogeneous but allows for rotation and/or shear. See also → Bianchi cosmological model.

→ anisotropic; → homogeneous; → cosmological; → model.

A variation in a property with direction, e.g. → cosmic microwave background anisotropy, → dipole anisotropy.

From → an-, privative prefix, + → isotropy.

1) (in humans) The joint between the foot and the leg, in which movement occurs in two planes.
2) The corresponding joint in a quadruped or bird; hock (Dictionary.com).

M.E. ankel, enkel, cognate with M.L.G., Du. enkel, O.H.G. anchal, enchil, O.Norse okkul.

Quzak, from quz, variant of kuž "humped," → convex.

The process in which the entire → mass of → two colliding → particles, one of → matter and one of → antimatter, is → converted into → radiant energy in the form of → gamma rays. See also → annihilation operator.

L. annihilatus, p.p. of annihilare "to reduce to nothing," from ad- "to" + nihil "nothing," from ne- "not" + hilum "small thing, trifle"

Nâbudi, from nâ- "not" + bud "to be, exist," from budan "to be, exist" + -i noun forming suffix.

In → quantum field theory, the operator that lowers → eigenstates one → energy level, contrarily to the → creation operator.

→ annihilation; → operator.

To make known publicly or officially; proclaim; give notice of (Dictionary.com).

M.E., from M.Fr. anoncer, O.Fr. anoncier "announce, proclaim," from L. annuntiare, adnuntiare "to announce, relate," literally "to bring news," from → ad- "to" + nuntiare "relate, report," from nuntius "messenger."

žâyidan, from prefix â- + Sogd., Munji žây- "to speak, to say," Yaghnobi žoy- "to read, sing," Yazghulami γay- "to call," Pers. (prefixed) afqân "lamentation, groaning;" Av. gā- "to sing," pairi.gā.vacah- "who sings the words around," bərəzi.gāθra- "singing high," gāθə- "song, gāthā;" cf. Skt. gā- "to sing;" O.Russ. gajati "to croak (ravens)"; Lith. giedoti "to sing" (Cheung 2007).

Covering the period of a year; occurring or happening every year or once a year.

Annual, from M.Fr. annuel, from L.L. annualis, blend of L. annuus "yearly," from annus "year" and L. annalis "yearly," from annus "year," from PIE *atnos, from *at- "to go" (Skt. a'tati "he goes, wanders").

Sâlâné, from sâl, → year, + âné "-ly".

The apparent, small displacement in position of a star during the year due to the → aberration of starlight. It depends on the → celestial latitude, and its maximum value is about 20''.50. See also → constant of aberration; → aberration orbit.

→ annual; → aberration.