wood grain vs woodgrain

wood grain and woodgrain both are nouns.

Word	Noun	Adjective	Verb	Adverb
wood grain	Yes	No	No	No
woodgrain	Yes	No	No	No

As nouns, wood grain and woodgrain are synonyms defined as:

Other synonyms of wood grain include woodiness.

wood grain (noun)	woodgrain (noun)
texture produced by the fibers in wood	texture produced by the fibers in wood