Green’s Dictionary of Slang

turn-in n.1

[turn in v.1 (1)]

a bed.

[UK]J. Greenwood Odd People in Odd Places 55: A regler turn-in, I mean, with sheets and that?
[UK]D. Stewart Dead Man’s Gold in Illus. Police News 13 Feb. 12/1: ‘[W]hat I would advise [...] would be a stiff glass of grog and a turn in’.