fire thorn vs firethorn

fire thorn and firethorn both are nouns.

Word	Noun	Adjective	Verb	Adverb
fire thorn	Yes	No	No	No
firethorn	Yes	No	No	No

As nouns, fire thorn and firethorn are synonyms defined as:

fire thorn and firethorn: any of various thorny shrubs of the genus Pyracantha bearing small white flowers followed by hard red or orange-red berries

Other synonyms of fire thorn include pyracanth, Pyracantha.

fire thorn (noun)	firethorn (noun)
any of various thorny shrubs of the genus Pyracantha bearing small white flowers followed by hard red or orange-red berries	any of various thorny shrubs of the genus Pyracantha bearing small white flowers followed by hard red or orange-red berries