房間，有時可簡稱「房」，包括廳，是一個建築物內的間隔空間，由牆、間板、屏風等劃出其範圍，又以門、窗、天、閘、出口、通道、走廊、樓梯、橋等，跟其他空間及外面的世界往來。
In a building, a room is any space enclosed within a number of walls to which entry is possible only by a door or other dividing structure that connects it either to a passageway, to another room, or to the outdoors, that is large enough for several persons to move about, and whose size, fixtures, furnishings, and sometimes placement within the building support the activity to be conducted in it.