1) Containerful 2) Crowd in a chamber 3) Studio capacity 4) The quantity a room will hold 
• (n.) As much or many as a room will hold; as, a roomful of men. • (a.) Abounding with room or rooms; roomy.
Room'ful adjective Abounding with room or rooms; roomy. 'A roomful house.' [ R.] Donne. Room'ful noun ; plural Roomfuls As much or many as a room will hold; as, a roomful of men. Swift. 
[n] - the quantity a room will hold
noun the quantity a room will hold