Definition of "comet"

comet

/ˈkɒmət/

noun
plural comets
1. (astronomy) A small Solar System body consisting mainly of volatile ice, dust and particles of rock whose very eccentric solar orbit periodically brings it close enough to the Sun that the ice vaporises to form an atmosphere, or coma, which may be blown by the solar wind to produce a visible tail.
  Quotations
  And They made by the lifting of Their hands, each god according to his sign, the Bright One with the flaring tail to seek from the end of the Worlds to the end of them again, to return again after a hundred years. Man, when thou seest the comet, know that another seeketh besides thee nor ever findeth out.
  1905, [Edward Plunkett,] Lord Dunsany, The Gods of Pegāna‎, London: Elkin Mathews, […]
2. A celestial phenomenon with the appearance of such a body.
  Quotations
  Upon his browes was pourtraid vgly death,And in his eies the furies of his heart,That ſhine as Comets, menacing reueng,And caſts a pale complexion on his cheeks.
  c. 1587–1588, [Christopher Marlowe], Tamburlaine the Great. […] The First Part […], 2nd edition, part 1, London: […] [R. Robinson for] Richard Iones, […], published 1592; reprinted as Tamburlaine the Great (A Scolar Press Facsimile), Menston, Yorkshire, London: Scolar Press, 1973, Act III, scene ii
3. Any of several species of hummingbird found in the Andes.