comet vs estraterrestrial body

comet and estraterrestrial body both are nouns.

Word	Noun	Adjective	Verb	Adverb
comet	Yes	No	No	No
estraterrestrial body	Yes	No	No	No

As nouns, estraterrestrial body is a hypernym of comet; that is, estraterrestrial body is a word with a broader meaning than comet:

comet: (astronomy) a relatively small extraterrestrial body consisting of a frozen mass that travels around the sun in a highly elliptical orbit
estraterrestrial body: a natural object existing outside the earth and outside the earth's atmosphere

Other hypernyms of comet include extraterrestrial object.

comet (noun)	estraterrestrial body (noun)
(astronomy) a relatively small extraterrestrial body consisting of a frozen mass that travels around the sun in a highly elliptical orbit	a natural object existing outside the earth and outside the earth's atmosphere