Green’s Dictionary of Slang

Rock, the n.

1. (UK Und.) the prison at Gibraltar, used for transported UK felons.

[UK]Leaves from Diary of Celebrated Burglar 113/1: It costs you nothing, flashing round, spending ‘sugar’ of the poor ‘wire’ who is now ‘doing’ his ‘lagging’ on the ‘rock’ (Gibraltar).

2. (also Big Rock) Alcatraz Federal prison on Alcatraz Island, California.

[US]A. Hynd We Are the Public Enemies 142: Four years after he checked into the Rock, Doc Barker tried to crash out.
[US]T. Runyon In For Life 148: He had seen correspondence indicating an early transfer to the Rock for me if there was a conviction.
[US]B. Jackson Thief’s Primer 37: Anybody who can’t get along in Leavenworth or Atlanta, who [...] can’t put up with a few little restrictions, is sent to the fuckin’ Rock.
[US]‘Red’ Rudensky Gonif 60: ‘Is there a blast, or are you going to the Big Rock?’ He meant Alcatraz Island.

3. (US Und.) Florida State Penitentiary, Raiford.

[US]J. Blake Ex Post Facto in Joint (1972) 45: The Queen of the Rock, a really beautiful faggot, was Bobby [...] Bobby and her current lover were discovered flagrante in an upstairs two-man cell, and taken to the Rock Lieutenant.

4. Rikers Island prison, New York City.

[US]J. Mills Panic in Needle Park (1971) 118: Mickey and I used to go together, when Bobby was on the rock, didn’t we, Mickey? [...] I really like those times, Mickey. I mean, of course I was sorry Bobby was locked up, but it was nice.
[US]Sepe & Telano Cop Team 151: ‘He must be on the “Rock” if he didn’t make bail.’ Telano was referring to Riker’s Island, where the city confines [...] all arrested youths between the ages of 16 to 20 years.
[US]T. Williams Crackhouse 66: He says no then stops and asks if maybe we’d met on ‘the Rock’ (Rikers Island prison).
[US]P. Beatty Tuff 34: ‘You know somebody in Rikers?’ ‘Please, I know much niggers on the rock.’.