Green’s Dictionary of Slang

(Aus. prison) the solitary confinement block.

1886

Eve. News (Sydney) 27 Apr. 7/4: We were put into the ‘moral’ for insubordination. I was shut up in a little cell 3ft by 6ft one way and 7ft by 6ft the other. There I was for six months, with only one hour’s exercise a day, and kept for the whole time on half-rations.