britt vs copepod crustacean

britt and copepod crustacean both are nouns.

Word	Noun	Adjective	Verb	Adverb
britt	Yes	No	No	No
copepod crustacean	Yes	No	No	No

As nouns, copepod crustacean is a hypernym of britt; that is, copepod crustacean is a word with a broader meaning than britt:

britt: minute crustaceans forming food for right whales
copepod crustacean: minute marine or freshwater crustaceans usually having six pairs of limbs on the thorax; some abundant in plankton and others parasitic on fish

Other hypernyms of britt include copepod.

britt (noun)	copepod crustacean (noun)
the young of a herring or sprat or similar fish	minute marine or freshwater crustaceans usually having six pairs of limbs on the thorax; some abundant in plankton and others parasitic on fish
minute crustaceans forming food for right whales