Green’s Dictionary of Slang

1. (Aus./N.Z. prison/und.) the punishment or solitary confinement cells.

[1785		Grose Classical Dict. of the Vulgar Tongue n.p.: Pound, a prison].
1953		I. Hamilton Till Human Voices Wake Us 26: [O]ne more word from you [...] it’ll be bread and water and the pound.
1962		J. McNeill How Does Your Garden Grow? (1974) 54: mick: Get sprung with it and [...] [t]hree days in the pound it’s likely to get yer.
1971		T.R. Shadbolt Bullshit and Jelly Beans 22: Danny spent a few days in the pound on bread and potatoes for threatening a screw who'd been picking on him.
1977		E. Torres Q&A 66: Learned my lesson [...] Federal pound. Forty-four months.
1982		G. Newbold Big Huey 25: You’re in jail now, son! Another peep from you and you’ll be down the fooking pound.
1990		Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Pound. Punishment cell. Thus, ‘to do pound’ is to suffer solitary confinement. Sometimes also refers to the segregation of protection prisoners.
1991		B. Payne Staunch 140: A week later she came back and she wasn't allowed to visit me; they told her I was down in the pound [punishment cells].
1999		D. Looser ‘Boob Jargon’ in NZEJ 13 34: pound n. Solitary confinement punishment cell.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 144/1: pound n. 1 (commonly the pound) a short-term solitary confinement punishment cell, or the detention unit of a prison.

2. (N.Z. prison) a cell reserved for unstable, at-risk inmates.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 144/2: pound 2 a cell for mentally unbalanced or 'at-risk' inmates.