periwinkle vs seafood

periwinkle and seafood both are nouns.

Word	Noun	Adjective	Verb	Adverb
periwinkle	Yes	No	No	No
seafood	Yes	No	No	No

As nouns, seafood is a hypernym of periwinkle; that is, seafood is a word with a broader meaning than periwinkle:

periwinkle: small edible marine snail; steamed in wine or baked
seafood: edible fish (broadly including freshwater fish) or shellfish or roe etc

periwinkle (noun)	seafood (noun)
edible marine gastropod	edible fish (broadly including freshwater fish) or shellfish or roe etc
small edible marine snail; steamed in wine or baked
chiefly trailing poisonous plants with blue flowers
commonly cultivated Old World woody herb having large pinkish to red flowers