acorn barnacle vs cirriped

acorn barnacle and cirriped both are nouns.

Word	Noun	Adjective	Verb	Adverb
acorn barnacle	Yes	No	No	No
cirriped	Yes	No	No	No

As nouns, cirriped is a hypernym of acorn barnacle; that is, cirriped is a word with a broader meaning than acorn barnacle:

acorn barnacle: barnacle that attaches to rocks especially in intertidal zones
cirriped: marine crustaceans with feathery food-catching appendages; free-swimming as larvae; as adults form a hard shell and live attached to submerged surfaces

Other hypernyms of acorn barnacle include barnacle, cirripede.

acorn barnacle (noun)	cirriped (noun)
barnacle that attaches to rocks especially in intertidal zones	marine crustaceans with feathery food-catching appendages; free-swimming as larvae; as adults form a hard shell and live attached to submerged surfaces