An Etymological Dictionary of Astronomy and Astrophysics
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A black amorphous substance produced by heating wood or other natural organic matter in the absence of air. It is used as a fuel.

M.E. charcole, maybe from cherre "char" + cole, → coal.

Zoqâl "live coal, charcoal," variant sokâr; Sogd. askâr; Pashto skor-; Khotanese skara, probably ultimately from Proto-Ir. *uz-gar-, from *uz- "out," → ex-, + *gar "to heat, kindle fire, cook;" cf. Tabari kalə "furnace," kəlen "ash;" Laki koira; Kurd. kulan, kulandan "to cook;" related to garm "warm;" cf. Skt. ghar- "to burn," PIE root *gwher- "to warm, be warm," → warm.

A black, hard mineral consisting of carbon and various carbon compounds. Coal is formed from the decomposition of ancient plants buried deep in the Earth's crust for millions of years. It is currently the most widely used substance to generate electricity and heat. Its combustion products are used as raw material for a variety of products including cement, asphalt, and plastics. Due to the harmful gases that it releases, the use of coal is constantly being reduced as alternative fuels are found.

M.E. cole, from O.E. col "charcoal, live coal;" (cf. O.Fr. kole, M.Du. cole, Du. kool, O.H.G. chol, Ger. Kohle, from PIE root *g(e)u-lo- "live coal" (cf. Irish gual "coal").

From zoqâl, → charcoal, + sang, → stone.

A prominent → dark nebula visible to the naked eye as a dark patch silhouetted against the starry band of → Milky Way in the Southern sky. It obscures an area of about 5 by 7 degrees on the sky and extends beyond the borders of → Crux into neighboring → constellations → Centaurus and → Musca. It lies at a distance of approximately 500 → light-years.

→ coal; sack, from M.E., from O.E. sacc, from L. saccus, from Gk. sakkos, of Semitic origin (cf. Heb. saq "sack").

Guni "sack;" zoqâl, → charcoal.

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.