Odobenus rosmarus vs seahorse

Odobenus rosmarus and seahorse both are nouns.

Word	Noun	Adjective	Verb	Adverb
Odobenus rosmarus	Yes	No	No	No
seahorse	Yes	No	No	No

As nouns, seahorse is a hypernym of Odobenus rosmarus; that is, seahorse is a word with a broader meaning than Odobenus rosmarus:

Odobenus rosmarus: a walrus of northern Atlantic and Arctic waters
seahorse: either of two large northern marine mammals having ivory tusks and tough hide over thick blubber

Other hypernyms of Odobenus rosmarus include sea horse, walrus.

Odobenus rosmarus (noun)	seahorse (noun)
a walrus of northern Atlantic and Arctic waters	small fish with horse-like heads bent sharply downward and curled tails; swim in upright position
	either of two large northern marine mammals having ivory tusks and tough hide over thick blubber