(n) :
a celestial body consisting mainly of ice, dust and gas in an (usually very eccentric) orbit around the Sun and having a "tail" of matter blown back from it by the solar wind as it approaches the Sun
(n) :
a celestial body consisting mainly of ice, dust and gas in an (usually very eccentric) orbit around the Sun and having a "tail" of matter blown back from it by the solar wind as it approaches the Sun