chatroom vs chat room

chatroom and chat room both are nouns.

Word	Noun	Adjective	Verb	Adverb
chatroom	Yes	No	No	No
chat room	Yes	No	No	No

As nouns, chatroom and chat room are synonyms defined as:

chatroom and chat room: a site on the internet where a number of users can communicate in real time (typically one dedicated to a particular topic)

chatroom (noun)	chat room (noun)
a site on the internet where a number of users can communicate in real time (typically one dedicated to a particular topic)	a site on the internet where a number of users can communicate in real time (typically one dedicated to a particular topic)