ˌopen ˈhouse noun

1. [countable] American English a day when a school or organization invites the public to come in and see the work that is done there:
Parents are invited to attend the open house next Thursday.

2. [uncountable] British English if it is open house at someone’s home, people are always welcome to visit at any time:
He kept open house for a wide range of artists and writers.

3. [countable] a party at someone’s house that you can come to at any time during a particular period:
We’re having an open house Sunday, noon to 5 pm.

4. [countable] American English an occasion when someone who is selling their house lets everyone who is interested in buying it come to see it

[TahlilGaran] Dictionary of Contemporary English ▲