Prison officers

[rarll]

Why are prison officers called screws

[Quizmonster]

Screw (in this particular slang sense) appeared in the mid 18th century to mean a false or skeleton key. Perhaps because prison officers carry many keys around with them, the word became attached to them over the next fifty years or so. As a result, the earliest-recorded reference in print for screw = warder dates from 1812. There is also a suggestion that the 'screw' was a name given to a mediaeval torture device, which would also have been used in prisons or even to a sort of treadmill that prisoners had to 'work' on.

[ARSENAL]

Years ago, as a punishment, prisoners used to have to turn a handle on a box about 10,000 odd times a day.  As they went on and on the handle became looser until the prison guard came back and turned the screw up to make it tighter.  That is where the word 'screw' came from.  (well according to an episode of Time Team I saw once).