stock room vs stockroom

stock room and stockroom both are nouns.

Word	Noun	Adjective	Verb	Adverb
stock room	Yes	No	No	No
stockroom	Yes	No	No	No

As nouns, stock room and stockroom are synonyms defined as:

stock room and stockroom: storeroom for storing goods and supplies used in a business

stock room (noun)	stockroom (noun)
storeroom for storing goods and supplies used in a business	storeroom for storing goods and supplies used in a business