balsa wood vs balsa

balsa wood and balsa both are nouns.

Word	Noun	Adjective	Verb	Adverb
balsa wood	Yes	No	No	No
balsa	Yes	No	No	No

As nouns, balsa wood and balsa are synonyms defined as:

balsa wood and balsa: strong lightweight wood of the balsa tree used especially for floats

balsa wood (noun)	balsa (noun)
strong lightweight wood of the balsa tree used especially for floats	forest tree of lowland Central America having a strong very light wood; used for making floats and rafts and in crafts
	strong lightweight wood of the balsa tree used especially for floats