comet Meaning, Definition & Usage

noun (astronomy) a relatively small extraterrestrial body consisting of a frozen mass that travels around the sun in a highly elliptical orbit

L. cometes, cometa, from Gr. comet, prop. long-haired, fr. to wear long hair, fr. hair, akin to L. coma: cf. F. comète.

(Astron.) A member of the solar system which usually moves in an elongated orbit, approaching very near to the sun in its perihelion, and receding to a very great distance from it at its aphelion. A comet commonly consists of three parts: the nucleus, the envelope, or coma, and the tail; but one or more of these parts is frequently wanting. See Illustration in Appendix.