animal house, n. — Green’s Dictionary of Slang

animal house n.

also animal farm, animal zoo

[the phr. gained international popularity with the release of the film Animal House (1978), starring John Belushi]

(US campus) a fraternity house that is generally rated the least efficient, the most degenerate and, overall, the one to avoid.

1967		D. Simmons ‘Terms Used in a Men’s Dormitory’ in AS XLII:4 227: animal zoo, n. phr. The name of a fraternity reputed to be the ‘worst house on campus’.
1971		Current Sl. V:4 8: Animal farm, n. Kappa Sigma Fraternity at the Universiy of Vermont.
1978		[film title] Animal House.
1989		H. Rawson Dict. of Invective (1991) 19: Two-footed animals are also encountered today on college campuses, living together in animal houses (fraternities or sororities).