comet

noun com·et \ˈkä-mət\

: an object in outer space that develops a long, bright tail when it passes near the sun

Full Definition of COMET

: a celestial body that appears as a fuzzy head usually surrounding a bright nucleus, that has a usually highly eccentric orbit, that consists primarily of ice and dust, and that often develops one or more long tails when near the sun

— com·e·tary \-mə-ˌter-ē\ adjective

— co·met·ic \kə-ˈme-tik, kä-\ adjective

See comet defined for English-language learners

See comet defined for kids

Origin of COMET

Middle English comete, from Old English cometa, from Latin, from Greek komētēs, literally, long-haired, from koman to wear long hair, from komē hair

First Known Use: before 12th century

Other Astronomy Terms

gibbous, nadir, nebulous, penumbra, retrograde, sidereal, syzygy, wane, wax, zenith

COMET Defined for Kids

comet

noun com·et \ˈkä-mət\

Definition of COMET for Kids

: a small bright heavenly body that develops a cloudy tail as it moves in an orbit around the sun

Word History of COMET

The tail of a comet looks rather like long hair streaming behind the head. The ancient Greeks named comets with the word komētēs, which means literally “long-haired.” This word comes from the noun komē, “hair on one's head” or “shock of hair.” The English word comet came from the Greek name for comets.