white potato vs white potato

white potato and white potato both are nouns.

Word	Noun	Adjective	Verb	Adverb
white potato	Yes	No	No	No
white potato	Yes	No	No	No

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