white poplar vs whitewood

white poplar and whitewood both are nouns.

Word	Noun	Adjective	Verb	Adverb
white poplar	Yes	No	No	No
whitewood	Yes	No	No	No

As nouns, white poplar and whitewood are synonyms defined as:

white poplar and whitewood: light easily worked wood of a tulip tree; used for furniture and veneer

Other synonyms of white poplar include true tulipwood, tulipwood, yellow poplar.

white poplar (noun)	whitewood (noun)
a poplar that is widely cultivated in the United States; has white bark and leaves with whitish undersurfaces	light easily worked wood of a tulip tree; used for furniture and veneer
light easily worked wood of a tulip tree; used for furniture and veneer