Definition of "gaoler"

The Grange is not a prison, Ellen, and you are not my gaoler.

1847 December, Ellis Bell [pseudonym; Emily Brontë], chapter XXIII, in Wuthering Heights: […], volume (please specify |volume=I or II), London: Thomas Cautley Newby, […]

One very important section of the denizens of Darkest England are the criminals and the semi-criminals. They are more or less predatory, and are at present shepherded by the police and punished by the gaoler.

1890, William Booth, chapter 7, in In Darkest England and the Way Out‎

A gaoler struck him, pushing him back in place in the hopeless, helpless line of prisoners.

1966, James Workman, The Mad Emperor, Melbourne, Sydney: Scripts, page 41