Green’s Dictionary of Slang

1. (US prison) the condemned cells.

1950		Goldin et al. DAUL 41/2: C. C. ’s. (P) The cells of those condemned to death; the death house. ‘Two new mickeys (new arrivals) hit the c.c.’s today for that knock-off (murder) in Brownsville.’.
1992		Bentley & Corbett Prison Sl. 105: D.C. also C.C. […] a security cell where the inmate is kept just prior to his execution, usually the 24-hour period prior to his scheduled execution time. This cell is called the ‘death cell’ or ‘condemned cell’ and is commonly known as the ‘D.C.’ or the ‘C.C.’.

2. attrib. use of sense 1.

1935

D. Lamson We Who Are About to Die 47: Tobacco, soap, pen points, thread, soda capsules, C.C. pills.

3. one who is awaiting execution on a capital charge.

1956

‘Charles Raven’ Und. Nights 106: A C.C. is a man condemned on the Capital Charge, and therefore awaiting execution.

4. (US prison) concurrent sentences.

1971–2

C. Shafer ‘Catheads [...] and Cho-Cho Sticks’ in Abernethy Bounty of Texas (1990) 200: CC, n. – concurrent sentences.

5. (N.Z. prison) Cell Confinement.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 39/1: CCs abbr. Cell Confinement Note: [...] the inmate spends specified number of days in the solitary confinement cell, the exact number of days being decided according to the severity of the inmate's offence [...] the inmate is stripped of his prison uniform and put in pyjamas. He is not allowed cigarettes or a lighter, nor is he allowed to order goods [...] or receive visits.