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

A specialist or expert in grammar.

From O.Fr. gramairien "learned man, person who knows Latin," agent noun from grammaire, → grammar.

Zabân-dasturdân, literally "knower of grammar," from zabân-dastur→ grammar + dân agent noun and present stem of dânestan, → know.

Of or relating to → grammar; conforming to standard usage.

From M.Fr. grammatical and directly from L. grammaticalis "of a scholar," from grammaticus "pertaining to → grammar."

Dastur-e zabâni, zabân-dasturidastur-e zabân, zabân-dastur, → grammar.

An inflectional category, basically pertaing to nouns and pronoun, which marks their relationship with other parts of the sentence. sentence. → accusative case, → nominative case, → genitive case, → dative case, → ablative case, → vocative case, → imperative case.

→ grammatical; → case.

A galaxy with prominent → arms that are clearly attached to the central → bulge or → bar spiraling continuously outward until they reach the edge of the visible disk. Some examples are: → Whirlpool galaxy (M51), M74 (NGC 628), and NGC 2997.

M.E. graunt, from O.Fr. grant, grand, from L. grandis "big, great," also "full-grown;" design, from M.E. designen, from L. designare "mark out, designate, appoint," from → de- "out" + signare "to mark," from signum→ sign; → spiral; → galaxy.

Kahkešân, → galaxy; mârpic→ spiral; farsâz, → perfect.

Any physical theory that unites the strong, electromagnetic, and weak interactions at high energy. It is hoped that GUTs can ultimately be extended to incorporate gravity. → theory of everything.

M.E. graunt, from O.Fr. grant, grand, from L. grandis "big, great," also "full-grown;" unified, p.p. of → unify; → theory.

Negâré, → theory; yegâneš, verbal noun of yegânestan, → unify; bozorg→ great.

A very hard, granular, → igneous rock of visibly crystalline texture consisting mainly of → quartz, → mica, and → feldspar that constitutes the bulk of the → continental crust.

From Fr. granit(e) or directly from It. granito "granite," originally "grained," p.p. adj. from granire "granulate, make grainy," from grano "grain," from L. granum, → grain.

The mottled appearance of the solar → photosphere, caused by → convective cells, resembling → granules, which rises from the interior of the Sun. Each granule has a mean size of about 1,000 km and an upward velocity of about 0.5 km/sec. Granules are separated by intergranular walls about 400 K colder. They emerge from the fragments of the preceding granules and their lifetimes are about 20 minutes.

From → granule + -ation a combination of -ate and -ion, used to form nouns from stems in -ate.

Dâne-bandi, from dâné, → grain, + bandi verbal noun of bastan, vastan "to bind, shut;" O.Pers./Av. band- "to bind, fetter," banda- "band, tie" (cf. Skt. bandh- "to bind, tie, fasten;" PIE *bhendh- "to bind;" Ger. binden; E. bind).

1) Geology: A term used for a sedimentary particle that is between 2 and 4 millimeters in size. Granules are larger than → sand but smaller than → pebbles. Granules have typically been rounded by abrasion during sedimentary transport (geology.com/dictionary).
2) One of the → convective cells constituting the solar → granulation.

→ grain + → -ule.

The edible, pulpy, smooth-skinned berry or fruit that grows in clusters on vines of the genus Vitis, and from which wine is made (Dictionary.com).

M.E., from O.Fr. grape "bunch of grapes, grape."

Angur "grape," from Mid.Pers. angur "grape;" cf. Khwarazmi 'nkyδ, Yidgha agidro, Munji aglero, Shughni angûrδ, related to quré "unripe grape."

1) A visual representation of data that displays the relationship among variables, usually cast along X and Y axes.
2) In → graph theory, a graph G = (V, E) consists of a set of objects V called vertices and a set E which contains unordered pairs of distinct elements of V called edges.

Short for graphic (formula), from L. graphicus "of painting or drawing," from Gk. graphikos "able to draw or paint," from graph(ein) "to draw, write" + -ikos, → ic.

Negâré, from negâr "picture, figure" (verb negârdan, negâštan "to paint"), from prefix ne-, O.Pers./Av. ni- "down; into," → ni-, + gâr, from kar-, kardan "to do, to make" (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build;" Av. kərənaoiti "he makes;" cf. Skt. kr- "to do, to make," krnoti "he makes, he does," karoti "he makes, he does," karma "act, deed;" PIE base *k^wer- "to do, to make").

The branch of → mathematics dealing with → graphs. In particular, it involves the ways in which sets of points (→ vertex) can be connected by lines or arcs (→ edge).

→ graph; → theory.

(Adj.) Pertaining to the use of diagrams, graphs, mathematical curves, or the like.
Math.: Pertaining to the determination of values, solution of problems, etc., by direct measurement on diagrams instead of by ordinary calculations.
(n.) A product of the graphic arts, as a drawing or print. A computer-generated image.

→ graph + → -ic.

A particular crystalline form of → carbon occurring as a soft, black, lustrous mineral. The carbon atoms in graphite are strongly bonded together in sheets. Because the bonds between the sheets are weak, other atoms can easily fit between them, causing graphite to be soft and slippery to the touch. Graphite conducts electricity and is used in lead pencils and electrolytic anodes, as a lubricant, and as a moderator in nuclear reactors. If graphite is subjected to high pressure, it will be transformed into → diamond.
Graphite is present in the → interstellar medium; it forms in circumstellar shells and supernova ejecta. In particular, the 2175 Å interstellar extinction feature is accounted for by small graphite grains.

From Ger. Graphit, from Gk. graph(ein) "to write, draw," so called because it was used for pencils, → graph + -it a suffix of chemical compounds, equivalent to E. -ite.

Same as → diffraction grating.

M.E. grating, M.L. grata "a grating," variant of crata, from crat-, stem of cratis "wickerwork."

Turi, from tur "fishing net, net, snare," variants târ "thread, warp, string," tâl "thread" (Borujerdi dialect), cognate with tanidan, tan- "to spin, twist, weave" (Mid.Pers. tanitan; Av. tan- to stretch, extend;" Skt. tan- to stretch, extend;" tanoti "stretches," tantram "loom;" tántra- "warp; essence, main point;" Gk. teinein "to stretch, pull tight;" L. tendere "to stretch;" Lith. tiñklas "net, fishing net, snare," Latv. tikls "net;" PIE base *ten- "to stretch").

The angle between the incident optical beam and the normal to the grating. It is the angle to which the grating must be set to place the desired wavelength at the center of the detector.

→ grating; → angle.

The measure of the light intensity diffracted from a grating.

→ grating; → efficiency.

One of thousands of long, narrow indentations in the surface of a → diffraction grating.

→ grating; → groove.

To move or tend to move under the influence of gravitational force.

From L. gravitatus, p.p. of gravitâre, from gravis "heavy," → gravity.

Gerânidan, infinitive of gerân, → gravity.

1) The universal phenomenon of attraction between material bodies. → Newton's law of gravitation.
2) The act or process of moving under the influence of this attraction.

Verbal noun of → gravitate.

Of or relating to or caused by → gravitation.

Adj. of → gravitation.