Abbreviation of fraternity house
frat house (plural frat houses)
- (US) A building in which the members of a fraternity reside or meet, especially one located on or near the campus of a college or university.
- 1922, Willa Cather, One of Ours, ch. 9,
- She wrote some awfully slushy letters to Phil Bowen, and he read them aloud at the frat house one night.