Green’s Dictionary of Slang

clink n.1

[either SE clink, to secure, to fasten securely, or onomat. noise of clinking chains; note WWI milit. clink, guard room]

1. [early 16C+] (also clinker, clinko, clinky, klink) prison or other form of detention, i.e. a guard-room .

2. [mid-18C+] (also clinkum) money.

3. [late 19C] (Aus. prison) a leg-chain.

4. [1900s] (US) a police station.