Green’s Dictionary of Slang

park n.1

[SE park, recreational area]

[early–mid-19C] a prison.

SE in slang uses

In compounds

park ape (n.)

see under ape n.

park palings (n.) (also park railings) [SE palings, a fence/railings, i.e. resemblance]

1. [early–mid-19C] the teeth.

2. [late 19C] a neck of mutton.