also: パーティー・ルーム
noun
party room; multipurpose room
A room in a venue, apartment building, or community center that can be rented or used for parties, gatherings, or events.
マンションのパーティールームで友達の誕生日会を開いた。
We held a friend's birthday party in the apartment building's party room.
この施設にはパーティールームがあり、
This facility has a multipurpose room that anyone can use by reservation.