Green’s Dictionary of Slang

(US prison) a strait-jacket.

1933		Ersine Und. and Prison Sl.
1938		C. Beaton Cecil Beaton’s N.Y. 99: ‘Look through that window – that’s where we keep the camisoles.’ ‘Do you mean straightjackets?’ ‘If you like to call them that.’.
1949		Monteleone Criminal Sl. (rev. edn).
1950		Goldin et al. DAUL 39/2: Camisole. (P) A strait jacket.
1960		(con. 1950-1960) R.A. Freeman Dict. Inmate Sl. (Walla Walla, WA) 23: Camisole – a straitjacket.