ladies' room

plural ladies' rooms

1. A room belonging to or intended for some or all women, particularly

   ...a hanging stair of fifty-one steps... leads to the main hall, ladies' room, and balconies.

   1825, James Haig, A Topographical and Historical account of the Town of Kelso, and of the Town and Castle of Roxburgh, page 137

   1 more example

   The assailants soon became masters of the whole house, except the room where the general was, and which was strongly barred, and they kept up a constant firing of musketry into the windows and doors, except into those of the ladies' room.

   1825, “Peleg Wadsworth”, in American Military Biography, page 198

2. A room belonging to or intended for some or all women
   1. historicalA waiting room in a railway station or other public building intended exclusively for women and usually including a separate women's lavatory.

      ...Passenger House, containing ticket office, baggage room, ladies' room, gentlemen's room, water closet, say 50 feet by 20 feet...

      1856, Journals of the Legislative Assembly of the Province of Canada, volume 14, number 1, page 71

      2 more examples

      Arconum—I found two chairs wanting in the gentlemen's room, and the bath room attached applied to other purposes; the ladies' room was clean, and properly furnished, with the exception of two basins which were removed; the privies and urinaries clean...

      1864 January 26, J.G. Lindsay, letter to P.P.L. O'Connel, §8

      He had no lady with him, and his excuse for being in the ladies' room was, the gentlemen's room was too filthy. The little room into which he had gone was the ladies' water-closet... There were signs plainly printed on the doors, showing which rooms were for gentlemen and which for ladies and over the entrance to the little room, from which appellee was ejected, is printed the words: "Ladies' Private Room."

      1875 January, John Scholfield, opinion of the Illinois Supreme Court in TW&W Ry Co v Williams

      Synonyms: bathroom, women's room

   2. euphemisticA public restroom intended for use by females.

      The women's toilet (as distinguished from the ladies' room in a speakeasy, the johnny at school, the little girls' room at a party in an apartment, and the wash-my-hands on a train) was clean enough.

      1935, John O'Hara, BUtterfield 8, Ch. ix, p. 279