Learner's definition of OPEN HOUSE
1 [count], US : an event in which an organization (such as a school or company) invites the public to visit in order to see the things that happen there
Westside High School will host an open house from 3 to 7 p.m. today, and all parents are invited to attend.
colleges holding open houses for prospective students
— called also "British"open day
2 [count], US : an event in which anyone who is interested in buying a particular house, apartment, etc., is invited to go inside and look at it 3 chiefly British : a home or other place in which guests or visitors are welcome