balsam willow vs willow

balsam willow and willow both are nouns.

Word	Noun	Adjective	Verb	Adverb
balsam willow	Yes	No	No	No
willow	Yes	No	No	No

As nouns, willow is a hypernym of balsam willow; that is, willow is a word with a broader meaning than balsam willow:

balsam willow: small shrubby tree of eastern North America having leaves exuding an odor of balsam when crushed
willow: any of numerous deciduous trees and shrubs of the genus Salix

Other hypernyms of balsam willow include willow tree.

balsam willow (noun)	willow (noun)
small shrubby tree of eastern North America having leaves exuding an odor of balsam when crushed	a textile machine having a system of revolving spikes for opening and cleaning raw textile fibers
	any of numerous deciduous trees and shrubs of the genus Salix