ear-shell vs sea-ear

ear-shell and sea-ear both are nouns.

Word	Noun	Adjective	Verb	Adverb
ear-shell	Yes	No	No	No
sea-ear	Yes	No	No	No

As nouns, sea-ear is a hyponym of ear-shell; that is, sea-ear is a word with a more specific, narrower meaning than ear-shell:

ear-shell: any of various large edible marine gastropods of the genus Haliotis having an ear-shaped shell with pearly interior
sea-ear: an abalone found near the Channel Islands

Other hyponyms of ear-shell include Haliotis tuberculata, ormer.

ear-shell (noun)	sea-ear (noun)
any of various large edible marine gastropods of the genus Haliotis having an ear-shaped shell with pearly interior	an abalone found near the Channel Islands