Green’s Dictionary of Slang

a former ‘kept woman’ who is now a common prostitute and works either from her own room or in a house of assignation.

1889–90

Barrère & Leland Dict. of Sl., Jargon and Cant II 27/1: Lone ducks, lones doves, quiet mice. Women who hire their apartments, here they receive gentlemen visitors, or who go with them to houses of assignation. A woman without a souteneur, one who tries as much as possible to evade observation, and to keep up a respectable appearance.