IPA: /ˈruːmfʊl/
KK: /rumfəl/
The total number of people or things that can fit in a room, or the group of people or things present in a room.
The roomful of students listened attentively to the teacher.
Roomful → It is formed from "room" (from Old English *rum*, meaning space or area) and "-ful" (meaning full of). The word "roomful" means full of space or area, typically referring to the amount of something that can fill a room.
Think of a 'room' being 'full' of something — that's what 'roomful' means.