Green’s Dictionary of Slang

bower n.

[ironic uses of SE bower, a shady grove]

1. (UK Und.) as the Bower, Newgate prison.

[UK]G. Andrewes Dict. Sl. and Cant.
[UK]Flash Dict.
[UK]G. Kent Modern Flash Dict.
[UK]Flash Dict. in Sinks of London Laid Open.
[UK]Duncombe New and Improved Flash Dict.
[US]Matsell Vocabulum.

2. (Aus.) a prison.

[Aus]Crowe Aus. Sl. Dict. 11: Bower, a prison.
[Aus]N. Pulliam I Travelled a Lonely Land (1957) 230/2: bower – jail.