stockroom vs stock room

stockroom and stock room both are nouns.

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

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

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

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