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

1) A machine for converting one form of energy into another.
2) Geometry: That which creates a line, a surface, a solid by its motion.

From L. generator "producer," from genera(re)→ generate + -tor a suffix forming personal agent nouns from verbs and, less commonly, from nouns.

Âzângar, from âzân the stem of âzânidan→ generate + -gar suffix of agent nouns, from kar-, kardan "to do, to make" (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build," Av. kərənaoiti "makes;" cf. Skt. kr- "to do, to make," krnoti "makes," karma "act, deed;" PIE base k^wer- "to do, to make").

Pertaining or according to → genetics or → genes.

From Gk. genetikos, from genesis "origin," → gene; → -ic.

The study of heredity and inheritance, of the transmission of traits from one individual to another, of how genes are transmitted from generation to generation.

From → genetic and → -ics.

The → grammatical case that marks a noun or pronoun typically expressing "possession" or "origin." In English, the genitive case of a noun is shown in writing by adding an s together with an appropriately positioned apostrophe or creating it by using the pronoun of. For instance: "John's house," or "the house of John." A → synthetic language would express the same idea by putting the name "John" in the genitive case. Also called → possessive case.

From O.Fr. genitif or directly from L. (casus) genitivus "case expressing possession, source, or origin," from genitivus "of or belonging to birth," from genitus, p.p. of gignere "to beget, produce," → generate; → case.

Dârešti, → possessive; kâté, → case..

1) An exceptionally intelligent person or one with exceptional skill in a particular area of activity.
2) Exceptional intellectual or creative power or other natural ability (Oxford Dictionaries).

From L. genius "tutelary deity or genius of a person;" originally "generative power," from gignere "beget, produce," → generate.

Farhuš, from far- intensive prefix "much, abundant; elegantly," → perfect, + huš, → intelligence. Farhuši, from farhuš + -i.

The deliberate and systematic extermination of a national, racial, political, or cultural group (Dictionary.com).

From Gk. genos "race, kind," → generate, + → -cide.

Nežâdkoši, from nežâd, → race, + koši, → -cide.

1) Biology: The usual major subdivision of a family or subfamily in the classification of organisms, usually consisting of more than one species.
2) Logic: A class or group of individuals, or of species of individuals.
3) A kind; sort; class (Dictionary.com).

From L. genus "race, stock, kind, gender;" cognate with Gk. genos "race, kind," and gonos "birth, offspring, stock," → generate.

Sardé, from Mid.Pers. sardag "sort, kind;" Av. sarrəδa- "kind, type."

A combining form meaning "the earth," used in the formation of compound words.

Geo-, form Gk. ge "earth, land, ground, soil."

Zamin, zami "earth, ground," from Mid.Pers. zamig "earth;" Av. zam- "the earth;" cf. Skt. ksam; Gk. khthôn, khamai "on the ground;" L. homo "earthly being" and humus "the earth" (as in homo sapiens or homicide, humble, humus, exhume); PIE root *dh(e)ghom "earth."

1) Relating to, measured from, or with respect to the center of the Earth.
2) Having the earth as a center. → geocentric coordinate system, → Geocentric Coordinate Time, → geocentric cosmology, → geocentric parallax, → geocentric system.

→ geo- + → center + -ic an adjective-forming suffix.

A coordinate system which has as its origin the center of the Earth.

→ geocentric; → coordinate; → system.

The proper time experienced by a clock at rest in a coordinate frame co-moving with the center of the Earth, i.e. a clock that performs exactly the same movements as the Earth but is outside the Earth's gravity well. TCG was defined in 1991 by the International Astronomical Union as one of the replacements for Barycentric Dynamical Time (TDB).

→ geocentric; → coordinate; → time.

A model of the Universe in which the Earth is centrally located and the Sun, planets, and stars revolve around the Earth.

→ geocentric; → cosmology.

The angle between the geocentric location vector and the → geodetic equator.

→ geocentric; → latitude.

The same as → geodetic longitude.

→ geocentric; → longitude.

The difference between the direction of an object as seen from a point on the surface of the Earth and the direction in which it would be seen from the Earth's center. Also known as → diurnal parallax.

→ geocentric; → parallax.

An ancient model of the Universe whereby all the celestial bodies travel around the Earth in circular orbits. Eudoxus of Cnidus (c. 390- c. 337 BC), one of Plato's pupils, maintained that all objects in the sky are attached to moving crystalline spheres, with the Earth at the centre. This model is often named → Ptolemaic system after its most famous supporter, the Greco-Roman astronomer Ptolemy.

→ geocentric; → system.

Of or relating to → geochemistry.

→ geochemistry; → -al.

A field of science that is concerned with the relative abundance, distribution, and the movement of → chemical elements in the → Earth's crust or other → solar system objects.

→ geo-; → chemistry.

The outermost part of Earth's atmosphere, a tenuous halo of hydrogen and some helium extending out to perhaps 15 Earth radii, which emits Lyman-alpha radiation when it is bombarded by sunlight.

From → geo- + → corona.

1) The shortest distance between two points in space (or → space-time). A geodesic on a sphere is an → arc of a → great circle. In the theory of → general relativity, freely falling bodies follow geodesic paths in space-time.
2) → geodetic.

From Fr. géodésique, → geodesy; → -ic.

Kehinrah "shortest path," from kehin, superlative of keh "small, little, slender" (related to kâstan, kâhidan "to decrease, lessen, diminish," from Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen;" Av. kasu- "small, little;" Proto-Iranian *kas- "to be small, diminish, lessen") + râh "path, way, road" (from Mid.Pers. râh, râs "way, street," also rah, ras "chariot;" from Proto-Iranian *rāθa-; cf. Av. raθa- "chariot;" Skt. rátha- "car, chariot," rathyā- "road;" L. rota "wheel," rotare "to revolve, roll;" Lith. ratas "wheel;" O.H.G. rad; Ger. Rad; Du. rad; O.Ir. roth; PIE base *roto- "to run, to turn, to roll").