Green’s Dictionary of Slang

queen’s woman n.

‘a prostitute who received medical attention under the terms of the Contagious Diseases Acts of the 1860s’ (OED).

Royal Commission on Cont. Dis. Act (Report) n.p.: Some of them are called queen’s women, and consider themselves a privileged class, and exhibit the printed order to attend the periodical examination as a certificate of health [F&H].