butternut vs white walnut

butternut and white walnut both are nouns.

Word	Noun	Adjective	Verb	Adverb
butternut	Yes	No	No	No
white walnut	Yes	No	No	No

As nouns, butternut and white walnut are synonyms defined as:

butternut and white walnut: North American walnut tree having light-brown wood and edible nuts; source of a light-brown dye

Other synonyms of butternut include butternut tree, Juglans cinerea.

butternut (noun)	white walnut (noun)
oily egg-shaped nut of an American tree of the walnut family	North American walnut tree having light-brown wood and edible nuts; source of a light-brown dye
North American walnut tree having light-brown wood and edible nuts; source of a light-brown dye