- a room or a group of related rooms, among similar sets in one building, designed for use as a dwelling.
- a building containing or made up of such rooms.
- any separated room or group of rooms in a house or other dwelling: We heard cries from an apartment at the back of the house.
- apartments, British. a set of rooms used as a dwelling by one person or one family.
- (often plural) any room in a building, usually one of several forming a suite, esp one that is spacious and well furnished and used as living accommodation, offices, etc
- another name (esp US and Canadian) for flat 2 (def. 1)
- (as modifier)apartment building; apartment house
1640s, “private rooms for the use of one person within a house,” from French appartement (16c.), from Italian appartimento, literally “a separated place,” from appartere “to separate,” from a “to” (see ad-) + parte “side, place,” from Latin partem (see part (n.)). Sense of “set of private rooms in a building entirely of these” (the U.S. equivalent of British flat) is first attested 1874.