fir vs wood

fir and wood both are nouns.

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

As nouns, wood is a hypernym of fir; that is, wood is a word with a broader meaning than fir:

fir (noun)	wood (noun)
any of various evergreen trees of the genus Abies; chiefly of upland areas	any wind instrument other than the brass instruments
nonresinous wood of a fir tree	a golf club with a long shaft used to hit long shots; originally made with a wooden head
	the trees and other plants in a large densely wooded area
	the hard fibrous lignified substance under the bark of trees