tailfin vs ornament

tailfin and ornament both are nouns.

Word	Noun	Adjective	Verb	Adverb
tailfin	Yes	No	No	No
ornament	Yes	No	Yes	No

As nouns, ornament is a hypernym of tailfin; that is, ornament is a word with a broader meaning than tailfin:

tailfin: one of a pair of decorations projecting above the rear fenders of an automobile
ornament: something used to beautify

Other hypernyms of tailfin include decoration, ornamentation.

tailfin (noun)	ornament (noun)
a stabilizer that is part of the vertical tail structure of an airplane	something used to beautify
one of a pair of decorations projecting above the rear fenders of an automobile

tailfin (verb)	ornament (verb)
	make more attractive by adding ornament, colour, etc.
	be an ornament to