Wiktionary
n. A room set aside for playing card games in.
Usage examples of "card-room".
Thus from the chart-room, which had become a sort of lounge and card-room, through a small barred window it was possible to see the man at the wheel, who, in his turn, commanded a view of part of the chartroom, but not of the floor.
The inspiriting sound of other carriages was heard, and continual accessions of portly chaperons and strings of smartly-dressed girls were received, with now and then a fresh gentleman straggler, who, if not enough in love to station himself near any fair creature, seemed glad to escape into the card-room.
In fact, it was George Paget, who'd commanded the 4th Lights in the charge, who put the thing to me point-blank in the card-room at White's (can't imagine what I was doing there.