french fries vs potato

french fries and potato both are nouns.

Word	Noun	Adjective	Verb	Adverb
french fries	Yes	No	No	No
potato	Yes	No	No	No

As nouns, potato is a hypernym of french fries; that is, potato is a word with a broader meaning than french fries:

Other hypernyms of french fries include Irish potato, murphy, spud, tater, white potato.

french fries (noun)	potato (noun)
strips of potato fried in deep fat	an edible tuber native to South America; a staple food of Ireland
	annual native to South America having underground stolons bearing edible starchy tubers; widely cultivated as a garden vegetable; vines are poisonous