Green’s Dictionary of Slang

playhouse n.

1. a brothel.

[UK] ‘Prodigals Resolution’ in Playford Pills to Purge Melancholy I 60: In Play-houses I’ll spend my days, / For they’re hung round with Plackets; / Ladies make Room, behold I come, / Have at your Knocking Jackets.

2. (US Und.) a prison known for its liberal regime, also attrib.

[US]Helena Wkly Herald (MT) 24 July 7/2: It was worse than boy’s play for the Sheriff to attempt to keep such a villain as Con Murphy [...] with known sympathizers on the outside, in such a play-house as the city jail.
[US]Abbeville Press & Banner (SC) 13 June 6/5: The jail is no playhouse [...] smnall cells with bars and [...] the hardest of beds.
[US]Wash. Herald (DC) 7 May 6/6: [By] removing the playhouse features from the District jail [he] tightened up the former lax discipline.
[US]J. Black You Can’t Win (2000) 93: The food was fair. There was no discipline [...] In prison parlance, the place was a ‘playhouse’.
[US]M.C. Sharpe Chicago May (1929) 261: Playhouse—easy prison.
[US]Goldin et al. DAUL 160/1: Playhouse. (P) Any prison in which discipline is less rigorous and living conditions more congenial than in most prisons.

3. (US prison) a small prison.

[US]D. Clemmer Prison Community (1940) 334/2: play house, n. A prison with a small population.
[US]‘Bill O. Lading’ You Chirped a Chinful!! n.p.: Jail [...] Playhouse.

4. (US Und.) ext. to non-prison contexts, e.g. a town with little law and order.

[US]W.R. Burnett High Sierra in Four Novels (1984) 393: I thought this town was a playhouse. That’s what I heard in Chio.

5. (US gay) a room filled with implements to augment sado-masochistic sex.

[US]B. Rodgers Queens’ Vernacular 184: torture room [...] playhouse.