- a party or reception during which anyone who wishes may visit to share in a celebration, meet a special guest, etc.
- a time during which a school, institution, etc., is open to the public for exhibition or for some specific occasion.
- a house hospitably open to all friends who may wish to visit it.
- keep open house, to be prepared to entertain visitors at any time: They keep open house for artists and writers.
- US and Canadian an occasion on which an institution, such as a school, is open for inspection by the publicAlso called (in Britain and certain other countries): open day, at-home
- keep open house to be always ready to provide hospitality
- US and NZ a house available for inspection by prospective buyers