sole vs flatfish

sole and flatfish both are nouns.

Word	Noun	Adjective	Verb	Adverb
sole	Yes	Yes	Yes	No
flatfish	Yes	No	No	No

As nouns, flatfish is a hypernym of sole; that is, flatfish is a word with a broader meaning than sole:

sole: right-eyed flatfish; many are valued as food; most common in warm seas especially European
flatfish: any of several families of fishes having flattened bodies that swim along the sea floor on one side of the body with both eyes on the upper side

Other hypernyms of sole include food fish.

As nouns, flatfish is a hypernym of sole; that is, flatfish is a word with a broader meaning than sole:

sole: lean flesh of any of several flatfish
flatfish: sweet lean whitish flesh of any of numerous thin-bodied fish; usually served as thin fillets

sole (noun)	flatfish (noun)
right-eyed flatfish; many are valued as food; most common in warm seas especially European	any of several families of fishes having flattened bodies that swim along the sea floor on one side of the body with both eyes on the upper side
the underside of footwear or a golf club	sweet lean whitish flesh of any of numerous thin-bodied fish; usually served as thin fillets
the underside of the foot
lean flesh of any of several flatfish

sole (adjective)	flatfish (adjective)
being the only one; single and isolated from others
not divided or shared with others

sole (verb)	flatfish (verb)
put a new sole on