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

To grow together; to come together so as to form one whole, to fuse. → merge; → fusion.

From L. coalescere, from co- + al-, stem of alere "to nourish, make grow" + -esce, from -escere, a suffix conveying an inchoative meaning.

Âhamidan, from â- nuance prefix + ham "together" (Av. hama- "similar, the same;" Skt. samah "even, level, similar, identical;" Gk. hama "together with, at the same time," homos "one and the same," PIE *samos "same," from base *sem- "one, together") + -idan infinitive suffix.

1) General: The act or state of growing together, as similar parts; the act of uniting by natural affinity or attraction; the state of being united.
2) Merging of the stars composing a → binary system after having undergone → supernova explosion. General relativity predicts that binary systems of → compact objects will emit energy in the form of → gravitational radiation, and that this loss of energy eventually will lead to the coalescence of the system.

Verbal noun from → coalesce.

A scenario for building up → massive stars through merging of → intermediate-mass protostars. It occurs in the cores of dense stellar clusters that have undergone core contraction due to rapid → accretion of gas with low → specific angular momentum. The required densities are, however, very high, 10⁸ stars pc^-3, which are extremely rare (Bonnell et al. 1998, MNRAS 298, 93).

→ coalescence; → model.

To move without further use of propelling power. → coasting flight, → coasting Universe.

M.E. coste, from O.Fr., from L. costa "rib, side," cf. Mid.Pers. kust, kustag "side, direction; district," Mod.Pers. xost, xwast "a beaten road; island;" PIE *kost- "leg, bone."

Rahâraftan, from rahâ "free, set free" (O.Pers. rad- "to leave," Skt. rah-, rahati "separates, leaves," Av. razah- "isolation;" PIE *redh-) + raftan "to go, walk" (Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").

The unpowered flight of a spacecraft or missile after propulsion cutoff or between the burnout of one stage and the ignition of the next.

Coasting, verbal adjective from → coast; → flight.

A Universe whose density is just less than or equal to the critical value and expands forever with no change in the expansion rate.

Coasting, verbal adjective from → coast; → Universe.

To → cover with a → thin  → layer of a → substance, as → aluminum over the → surface of a → mirror, → aluminize.

Verb from noun coat, from M.E. cote, from O.Fr. cote "coat, robe," from some Germanic source; cf. O.S. kot "woolen mantle," O.H.G. chozza "cloak of coarse wool," Ger. Kotze "a coarse coat," of unknown origin.

Andudan, variant andâyidan, from Mid.Pers. handudan, from O.Iranian *ham-dâvaya-, from ham- "together" + *dâvaya-, from dav- "to rub, clear," cf. Av. dav- "to clean, polish," Skt. dhâv-, PIE *dheu- "to shine".

An open cluster of about 40 stars at the border of → Vulpecula and → Sagitta. It has an apparent size of about 1° and lies 420 → light-years away. Also called Collinder 399 and → Brocchi's Cluster. Six of its brighter stars, of sixth and seventh magnitude, are lined up in a nearly perfect row, from the center of which four stars form a hook to resemble the coathanger shape. To the naked eye, it appears as an unresolved patch first recorded by the Persian astronomer Sufi in A.D. 964. It was later rediscovered by Giovanni Battista Hodierna (1597-1660). The Coathanger shares roughly the same motion with several other clusters, including the → Pleiades.

→ coat; hanger, from hang, M.E. han(i)gen, fusion of O.E. hon "suspend" and hangian "be suspended;" also probably influenced by O.N. hengja "suspend" and hanga "be suspended" (cf. O.Frisian hangia, Du. hangen, Germ. hängen).

Raxtâviz, from raxt "clothes, garment, wearing apparel" + âviz "hang," → pendulum.

A → thin → layer of a → substance spread over a → surface.

Noun from → coat; → -ing.

A silver gray, brittle, hard metallic → chemical element which is highly magnetic; symbol Co. → Atomic number 27; → atomic weight 58.9332; → melting point 1,495°C; → boiling point about 2,870°C; → specific gravity 8.9 at 20°C. It is used in many → alloys, and in particular its compounds have been used since ancient times (Egyptians, Persians, Greeks) to produce a blue color in glass and ceramics. Cobalt was discovered in 1735 by the Swedish chemist Georg Brandt (1694-1768). It has several radioactive isotopes, including Co-56, half-life about 77 days, Co-57, 272 days, Co-58, 71 days, Co-60, 5.27 years. The → light curve of → type I supernovae is explained by the radioactive decay of nickel-56 through cobalt-56 to iron-56.

From Ger. kobold "evil spirits or goblins," who were superstitiously thought to cause trouble for miners, since the mineral contained arsenic which injured their health and the metallic ores did not yield metals when treated with the normal methods.

Geology: A → sedimentary particle that is between 64 and 256 mm in size. Cobbles are larger than → pebbles but smaller than → boulders. Cobbles have typically been rounded by abrasion during sedimentary transport (geology.com/dictionary).

From M.E. cobill, kobill, probably a diminutive of M.E. *cob, *cobb, ultimately from Proto-Germanic *kubb- ("lump; round object") + -le.

Qolve, variant of gorde "kidney."

A web spun by a spider to entrap its prey; a single thread spun by a spider; something resembling a cobweb; anything finespun, flimsy, or insubstantial (Dictionary.com).

M.E. coppeweb, derivative of O.E. -coppe "spider" in atorcoppe "poison spider;" + → web.

Karu "cobweb, web," variants kari, kartané, kartiné, kârtanak, kârtané, kare tan (all in Dehxodâ), (Malâyeri, Hamadâni) kâtena, (Gilaki) kârtang, (Kermâni) kerâš, (Qêyeni) kalaš, (Qomi) kârye, (Tabari) kel, kuli, (Yazdi) kare, from *kar-, *kâr-, *kel- "to weave;" cf. (Ormuri, in Pakistan, Afghanistan) gal-/galôk- "to weave;" PIE base *ker- "to weave; rope."

An emission nebula located about 3,000 light-years away toward the → constellation  → Cygnus. It is thought to be a region of active → star formation.

Cocoon, from Provençal Fr. coucoun, from O.Fr. coque "egg shell, nut shell," L. coccum "berry," from Gk. kokkos "berry, seed;" → star; → nebula.

Miq, → nebula; pilé "the silkworm's cocoon; a purse", cf. Skt. patta- "woven silk."

A star hidden in a dense envelope of gas and dust which is a strong source of infrared emission.

→ Cocoon nebula; → star.

1) A system used for brevity or secrecy of communication, in which arbitrarily chosen words, letters, or symbols are assigned definite meanings.
2) Computers: The symbolic arrangement of statements or instructions in a computer program in which letters, digits, etc. are represented as binary numbers; the set of instructions in such a program (Dictionary.com).

M.E., from O.Fr. code, from L. codex "book, book of laws," later form of caudex "tree trunk," hence "document made up of wooden tablets."

Ramz "secret writing, enigma," loan from Ar.

The complement of → declination; the angular distance along a great circle from the celestial pole, i.e., 90° - declination.

Codeclination, from → co- + → declination.

Hamvâkil, from ham-, → co-, + vâkil, → declination.

A manuscript text in book form which was common before the invention of printing. The codex is the earliest known form of a bound book which replaced the scroll. It was a Roman invention. → Dresden codex.

From L. codex "book," → code.

Nebigân, from nebi / nepi / nevi "book, scripture," from Mid.Pers. nibêg "writing, scripture, book," related to neveštan, → write, + -gân suffix denoting collective nature.

The set of values that a → function is allowed to take (i.e. may possibly come out of a function), as opposed to the → range.

→ co-; → domain.

1) Math.: A number or letter placed before an algebraic expression to indicate that the expression is to be multiplied by that factor, e.g. in the expression 2 x³, 2 is the coefficient of x³. In general, any factor of a product is called the coefficient of the product of the remaining factors.
2) Physics: Factor which measures some specified property of a given substance, and is constant for that substance under given conditions, such as the coefficient of friction. → factor.

Hamgar, from ham- "together," → com- + -gar agent suffix, 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."

A quantity that indicates a property of fluids and is defined by the ratio of shearing → stress to the rate of change of shearing → strain. It is also simply called viscosity. The coefficient of viscosity is expressed by: μ = (F/A) / (dv/dy), where F is the force required to maintain a steady velocity difference dv between any two parallel layers of the fluid, A is the area of the layers, and dv/dy is the → velocity gradient between two points separated by a small distance measured at right angles to the direction of flow. The unit of viscosity is that of force times distance divided by area times velocity. Thus, in the cgs system, the unit is 1 dyne.cm/cm².(cm/s), which reduces to 1 dyne.s/cm². This unit is called 1 → poise.

→ viscosity; → coefficient.