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

1) No thing; not anything; naught.
2) Nonexistence; nothingness.

M.E., from O.E. nathing, nathinc, from nan "not one," → non-, + → thing.

Mid.Pers. hêc, hêc(i), hâca "any."

The qualifier of a medium in which the → optical depth is large, significantly smaller than 1.

→ optically; → thin.

The mathematical process that makes a curve smooth.

Verbal noun of → smooth.

A low-pass filter designed to reduce the amplitude of a ripple while freely passing the direct current obtained from a rectifier or direct-current generator. Also known as smoothing filter.

→ smoothing; → circuit.

The transit of a celestial object, especially the Sun, across the meridian due south of the observer.

Verbal noun from → south (v.).

Gozar-e daštar-su, literally "passage southward," from gozar, → passage; daštar→ south; su, → direction.

A galaxy that appears as an extraordinary thin and long figure on the sky because of its → edge-on orientation, highly flattened stellar → disk, and absence of a → bulge component. Superthin galaxies are → gas-rich and have optically diffuse disks with little internal absorption, as well as low emission-line intensity ratios and slowly rising → rotation curves. They seem to be among the least evolved disk galaxies in the local Universe, having undergone only minimal dynamical heating, → star formation, and → angular momentum transport. Examples are: UGC 7321, UGC 3697, UGC 9242.

→ super-; → thin; → galaxy.

Any theory that attempts to describe all the forces of nature including gravity in a single mathematical formalism; e.g. → grand unified theory. → string theory.

→ theory; every; M.E. every, everich; O.E. æfre ælc "ever each;" → thing.

Negaré, → theory; hamé, → all; ciz, → thing.

Having relatively little extent from one surface or side to the opposite; not thick. → optically thin; → superthin galaxy.

M.E. thyn(ne), O.E. thynne, from P.Gmc. *thunnuz, *thunw- (cf. W.Fris. ten, M.L.G. dunne, Du. dun, O.H.G. dunni, Ger. dünn), from PIE *tnus-, *tnwi-, from base *ten- "stretch;" cf. Pers. tonok "thin, slender," → attenuate.

Nâzok, from Mid.Pers. nâzuk, nâzik "tender, gentle."

A disk component of a → spiral galaxy containing → stars, → gas, and → dust which are confined to the galaxy's → plane of rotation. In contrast to → thick disks, thin disks contain the bulk of the → baryonic matter in spiral galaxies. For example, on the order of 60-90% of the baryonic matter in the → Milky Way is located in the thin disk. The scale height of the thin disk in the Milky Way is about 400 → light-years, whereas its scale length is about 10,000 light-years. Moreover, the outer regions of thin disks appear to be bent by the → warp phenomenon. The thin disks of spiral galaxies are active sites of → star formation, especially in the spiral arms. For this reason, stars in the thin disk tend to be relatively young. Thin disk stars also tend to be → metal-rich compared with thick disk and → halo stars, and typically have a → metallicity similar to that of the Sun.

→ thin; → disk;

A lens whose thickness is considered small in comparison with the distances generally associated with its optical properties. Such distances are, for example, radii of curvature of the two spherical surfaces, primary and secondary focal lengths, and object and image distances. → thick lens.

→ thin; → lens.

1) A material object without life or consciousness; an inanimate object.
2) Some entity, object, or creature that is not or cannot be specifically designated or precisely described.
3) Anything that is or may become an object of thought (Dictionary.com).

M.E. thing; O.E. þing "meeting, assembly, discussion;" cf. O.Norse þing "assembly, meeting, council;" O.Frisian thing "assembly, action, matter, thing;" O.Saxon thing; O.Du. dinc "law suit, matter, thing;" M.Du. ding; Du. ding; O.Ger. ding, dinc "assembly;" M.H.G. dinc "assembly;" Ger. ding "matter, affairs, thing." Hence, the word originally meant "assembly, meeting," then came to mean a specific issue discussed at such an assembly, and finally came to indicate "an object."

Ciz, from Mid.Pers. ciš, tis "thing, affair;" O.Pers. cišciy "anything."

To employ one's mind rationally and objectively in evaluating or dealing with a given situation.

M.E. thinken, variant of thenken, O.E. thencan; P.Gmc. *thankjan (cf. O.Fris. thinka, O.S. thenkian, O.H.G. denchen, Ger. denken, Goth. thagkjan).

Andišidan, infinitive from andiš-; Mid.Pers. handeš-, handešidan "to think, consider, reflect," ultimately from Proto-Iranian *ham-dis-, from *ham- "together, with, same," → syn- + *dis- "form, appearance," cf. Av. daēs- "to show," daēsa- "sign, omen;" Mod.Pers. dis, disé "form, appearance," variants -diz, -diš; Mid.Pers. dêsag "form, appearance," dêsidan "to form, build;" Sogd. andiš "to seem," andêš "to show," andêšik "appearing;" cf. Skt. deś- "to show, point out;" PIE *deik- "to show" (cf. Gk. deiknumi "to show," dike "manner, custom;" L. dicere "to utter, say;" O.H.G. zeigon, Ger. zeigen "to show;" O.E. teon "to accuse," tæcan "to teach").