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

Same as → weak equivalence principle.

→ universality; → free; → fall.

The hypothesis whereby there exists a universal parent → distribution function which describes the stellar → initial mass function in individual star forming events. A consensus appears to have emerged in the community that the stellar IMF is largely invariant for star formation conditions as are found throughout the Local Group of galaxies at the present time. For details and discussion see Pavel Kroupa (2012), Recent advances on IMF research, arXiv.org/abs/astro-ph/1210.1211, and references therein.

→ universality; → initial mass function.

1) The totality of all matter and energy that exists in the vastness of cosmos whether known to human beings or not. Related concepts: → world, → cosmos, → multiverse.
2a) Math.: A → set made of → subsets that contains all the elements relevant to a particular discussion or problem.
2b) Statistics: The entire population under study.
See also: → all, → general, → omni-, → public, → total.

M.E., from O.Fr. univers, from L. universum "the universe," noun use of neuter of adj. universus "all together," literally "turned into one," from unus, → one, + versus, p.p. of vertere "to turn," akin to Pers. gar-, gardidan "to turn, to change" (Mid.Pers. vartitan; Av. varət- "to turn, revolve;" cf. Skt. vrt- "to turn, roll," vartate "it turns round, rolls;" L. vertere "to turn;" O.H.G. werden "to become;" PIE base *wer- "to turn, bend").

1) Giti "world, material world, time," variants jahân, keyhân, geyhân "world;" Mid.Pers. gêhân "world," gêtig "the material world; wordly;" Av. gaēθā- "being, world, matter, mankind," gaya- "life, manner of living", root gay- "to live" (present tense jiva-), O.Pers. gaiθā- "live-stock," cognate with Skt. jīv- "to live," jīva- "alive, living;" Gk. bios "life," L. vivus "living, alive," vita "life;" PIE base *g^wei- "to live" (cf. O.E. cwic "alive;" O.C.S. zivo "to live;" Lith. gyvas "living, alive;" O.Ir. bethu "life," bith "age;" Welsh byd "world"). The Pers. words zistan "to live," zendé "alive," zendegi "life," and jân "vital spirit, soul; mind" belong to this family.
2) Hargân, from har "every, all, each," → holo-, + -gân suffix forming plural entities, from Mid.Pers. -gânag, -gâna, on the model of hamegân, → public.

An institution of higher education composed of several faculties for teaching and research and authorized to grant academic degrees.

M.E., from O.Fr. universitei, from M.L. universitatem (nominative. universitas), in L.L. "corporation, society," from L., "the whole, aggregate," from universus "whole, entire," → universe.

Dânešgâh, from dâneš, → science, + -gâh "place; time" (Mid.Pers. gâh, gâs "time;" O.Pers. gāθu-; Av. gātav-, gātu- "place, throne, spot;" cf. Skt. gâtu- "going, motion; free space for moving; place of abode;" PIE *gwem- "to go, come").

1) Having one meaning only.
2) A word or term that has only one meaning

L.L. univocus, from L. → uni- + voc-, vox, → voice. "voice,"

The character of being → univocal. Same as → monosemy.

→ univocal; → ity.

Math.: A → variable or → function whose → value is to be found.

→ un-, + known, p.p. of → know.

Uncommon, unusual. → extraordinary.

→ un-; → ordinary.

A light whose electric vector of vibration is randomly oriented. Light is an → electromagnetic wave possessing an electric vector and an associated orthogonal magnetic vector. Both vectors are → transverse to the axis of propagation. In unpolarized light the electric and magnetic vibrations occur in all possible planes. Ordinary light emitted by the Sun, by a living room lamp, or by a candle flame is unpolarized light. → polarization.

→ un-; → polarized light.

Not qualified; not fit; lacking requisite qualifications (Dictionary.com).

→ un-; → qualified.

A star whose light is not affected by→ interstellar absorption. → reddening

→ un-; → reddened star.

Describing an image whose constituent or elementary parts are not resolved. → unresolved source.

→ un- + → resolved.

A source of radiation whose angular size is too small for details of its structure to be revealed.

→ unresolved; → source.

An image in which finer details are not visible. → blurred image

→ un-; → sharp image.

A process for amplifying fine details in a registered image. Generally speaking, the process consists of creating a mask which contains larger scale features of the image and then subtracting the mask from the initial image.

→ un-; → sharp; → masking.

Not → stable, as in → unstable atom, → unstable equilibrium.

→ un-; → stable.

An atom whose nuclei → decay by → radioactivity.

→ unstable; → atom.

An equilibrium state of a system in which if a small perturbation away from equilibrium is applied, the system will move farther away from equilibrium state. For example, mechanical equilibrium in which the potential energy is a maximum, as a sphere placed on top of a hill. Mathematically, if the second derivative of the energy with respect to the coordinate of interest is negative, the system is in an unstable equilibrium. → stable equilibrium.

→ unstable; → equilibrium.

The brightest star as well as the Alpha star of → Serpens, thus also known as α Serpentis. It is a third magnitude (V = 2.65) an orange giant of spectral type K2 with a radius 15 times as large as that of the Sun and a surface temperature of 4300 kelvins. It is approximately 73.2 light years from Earth. Unukalhai is in fact a triple star system. The second star (α Serpentis B) is 58 arcseconds from the primary and has a magnitude of 11.8. The third star (α Serpentis C), 13th magnitude, lies 2.3 arcminutes from A. Other designations: Cor Serpentis, HR 5854, HD 140573.

From Ar. 'unuq al-hayyah (عنق‌الحیه) "Neck of the Snake," from 'unuq "neck" + al-hayyah "snake."

To, toward, or in a more elevated position.

M.E. up(pe) (adv.), O.E. up(p) "to a higher position;" cf. O.Frisian up, O.S. up, M.Du. up, op, O.N. upp; O.H.G. uf; (Ger. auf), Goth. iup.

Bâlâ "up, above, high, elevated, height" (related to boland "high," borz "height, magnitude" (it occurs also in the name of the mountain chain Alborz), Lori dialect berg "hill, mountain;" Mid.Pers. buland "high;" O.Pers. baršan- "height;" Av. barəz- "high, mount," barezan- "height;" cf. Skt. bhrant- "high;" L. fortis "strong" (Fr. & E. force); O.E. burg, burh "castle, fortified place;" Ger. Burg "castle;" Goth. baurgs "city;" E. burg, borough; Fr. bourgeois, bourgeoisie, faubourg); PIE base *bhergh- "high."