Selene vomer vs horsehead

Selene vomer and horsehead both are nouns.

Word	Noun	Adjective	Verb	Adverb
Selene vomer	Yes	No	No	No
horsehead	Yes	No	No	No

As nouns, horsehead is a hypernym of Selene vomer; that is, horsehead is a word with a broader meaning than Selene vomer:

Selene vomer: similar to moonfish but with eyes high on the truncated forehead
horsehead: any of several silvery marine fishes with very flat bodies

Other hypernyms of Selene vomer include Atlantic moonfish, dollarfish, horse-head, horsefish, moonfish, Selene setapinnis.

Selene vomer (noun)	horsehead (noun)
similar to moonfish but with eyes high on the truncated forehead	any of several silvery marine fishes with very flat bodies