Definitionen
1.NounA 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.
2.NounA celestial phenomenon with the appearance of such a body.
3.NounAny of several species of hummingbird found in the Andes.