Being socially correct, we request the location of the facilities, the lavatory, or lav, from the Latin lavatorium, literally a “place for washing. “ Younger Americans favor the can (c.1900) or the head; possibly an editorial on how they relate to authority or from the original location of the ship’s facilities in the bulkhead. Middle aged folk ask for the washroom (c.1878), the powder-room (c.1920s) or the rest-room. Some still call for the toilet (c.1820s) from the French toilette, diminutive of toile, the cloth once covering the table on which sat one’s preparations.
The British middle class prefers the loo from lieu, “the place” or the French l’eau, “water,” making for the warning cry “Guardez l’eau, “ Mind the water!”— supposedly called out in the days before modern plumbing, when emptying chamber pots from upper-story buildings. Others suggest it is a misreading of room number 100, supposedly a common European toilet designation.The water closet dates from 1755 when it moved into the house from outside, then shortened to the W.C. (C.19). All this comes courtesy of Sir Thomas Crapper, developer of the modern toilet bowl, as per his biography, Flushed with Pride.