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.
Origin of open house
First recorded in 1520–30
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for open house
Historical Examples of open house
There was also an open-house at your own apartment during that period of time, was there not?Warren Commission (8 of 26): Hearings Vol. VIII (of 15)
The President's Commission on the Assassination of President Kennedy
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
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012