Green’s Dictionary of Slang

pen n.2

also penn
[abbr.]

1. (20C+ use mainly US) a penitentiary, spec. Millbank, London.

[WI]C. Rampini Letters from Jamaica 23: Her term of ‘labour at the Penn’ as the negroes jocularly call it.
[US]Nat. Police Gaz. (NY) 20 Dec. 11/3: He was convicted and sent to the ‘Pen’.
[US]C.E. Craddock In the Tennessee Mountains 66: ‘What wat it ez happened at the Pen?’ [...] ‘They put him right inter the forge at the Pen, an’ he tuk ter the work like a pig ter carrots.’ The ex-convict [...] cast his eye disparagingly.
[US]J. Flynt Tramping with Tramps 105: I saw a man go into the Fort Madison ‘pen’.
[UK]Globe (London) 25 Nov. 1/5: Newgate was known by its guests as ‘the Gate,’ Tothill Fields as ‘the Downs,’ and Millbank Penitentiary as ‘the Tench’ or ‘the Pen’.
[US]H. Hapgood Autobiog. of a Thief 38: If a thief wants to keep out of the ‘pen’ or ‘stir,’ (penitentiary) capital is a necessity.
[US]J. Lait ‘Charlie the Wolf’ Beef, Iron and Wine (1917) 57: This here is a dangerous young can’idate for the pen.
[US]J. Tully Jarnegan (1928) 152: I got word that the Warden at that Eastern pen would give me every facility to make a great prison picture there.
[US](con. 1920s) J.T. Farrell Young Manhood in Studs Lonigan (1936) 257: He saw himself in the pen for a manslaughter charge.
[US]Mezzrow & Wolfe Really the Blues 44: I had done two bits in the pen.
[US]C. Himes Crazy Kill 74: Looks a little like Country Boy used to look ’fore they sent him to the pen.
[US]‘Iceberg Slim’ Pimp 43: Your Honour, don’t send me to the pen.
[US]V.E. Smith Jones Men 53: They know people don’t like it in the pen.
[US] Ice-T ‘Grand Larceny’ 🎵 The only way to stop the stealin’ / Is throw me in the pen.
[US] Dr Dre ‘Stranded on Death Row’ 🎵 To my motherfuckin homies doin time In the pen and the county jail / Mobbin with your blues on, mad as hell.
D. Nelson Inner Piece 37: The Graybar Hotel. The Joint. Stir. ‘Q’. The Pen. Most of these names he’d heard before.
[UK]S. Kelman Pigeon English 139: My auntie taught me, she learned it [i.e. forgery] in the pen.
[US]W. Henderson City of Nightmares pt 2 v: The Pen ain’t safe dark hours of the night, / they might want a see if your ass really tight.
[UK]K. Koke ‘Bring Me Down (Intro)’ 🎵 Please friend, I don't wanna squeeze 10 / I wanna make g’s I don't wanna see pen.
[US]C.D. Rosales Word Is Bone [ebook] He looked hard, man. Like homies look right after they been let out the pen.
[UK]G. Krauze What They Was 14: [F]resh out of pen after a year and a half .

2. (US) a holding cell in a police station.

[US]H. Williamson Hustler 176: They got me down to the station, took me back and put me in the pen.
[US]Sepe & Telano Cop Team 149: Frankie was booked for burglary and lodged in the precinct pen.

In compounds