Odobenus rosmarus vs sea horse

Odobenus rosmarus and sea horse both are nouns.

Word	Noun	Adjective	Verb	Adverb
Odobenus rosmarus	Yes	No	No	No
sea horse	Yes	No	No	No

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

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

Other hypernyms of Odobenus rosmarus include seahorse, walrus.

Odobenus rosmarus (noun)	sea horse (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