amphipod vs whale louse

amphipod and whale louse both are nouns.

Word	Noun	Adjective	Verb	Adverb
amphipod	Yes	No	No	No
whale louse	Yes	No	No	No

As nouns, whale louse is a hyponym of amphipod; that is, whale louse is a word with a more specific, narrower meaning than amphipod:

Other hyponyms of amphipod include beach flea, sand flea, sand hopper, sandhopper, skeleton shrimp.

amphipod (noun)	whale louse (noun)
a kind of malacostracan crustacean	amphipod crustacean parasitic on cetaceans