fiberboard vs fibreboard

fiberboard and fibreboard both are nouns.

Word	Noun	Adjective	Verb	Adverb
fiberboard	Yes	No	No	No
fibreboard	Yes	No	No	No

As nouns, fiberboard and fibreboard are synonyms defined as:

fiberboard and fibreboard: wallboard composed of wood chips or shavings bonded together with resin and compressed into rigid sheets

Other synonyms of fiberboard include particle board.

fiberboard (noun)	fibreboard (noun)
wallboard composed of wood chips or shavings bonded together with resin and compressed into rigid sheets	wallboard composed of wood chips or shavings bonded together with resin and compressed into rigid sheets