copepod vs britt

copepod and britt both are nouns.

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

As nouns, britt is a hyponym of copepod; that is, britt is a word with a more specific, narrower meaning than copepod:

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

Other hyponyms of copepod include brit, cyclops, water flea, fish louse.

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