Name of Thrones
When nature calls, you use “The John” because England’s earliest flush lavatory was developed by Sir John Harrington, godson of Elizabeth I, although he called his creation “Ajax.”
Centuries later, British manufacturer Thomas Crapper developed the ballcock, a flushing mechanism still used today. His name appeared on these widely-used flush toilets in Europe, which became known as “crappers.”
Brits also call the toilet “the loo.” Before flush toilets, many Europeans did their thing in chamber pots, then threw the contents onto the street below, a practice which now might get you arrested. Before throwing, the courtesy was to yell out “Guardez l’eau!” (“Look out for the water!”), which eventually got shortened to just “loo” to mean toilet.
“Lavare” means to “to wash” in Latin, and this is the source of the word “latrine.” English speakers have been using this term for about 350 years.
“Toilette,” the French word from which we get “toilet,” means dressing room, and itself comes from the word “toile,” or cloth. In the 1600’s, the toilet was the process of doing your hair, clothes, makeup, etc. By 19th century America, this term referred to the room where this process occurred, and more particularly, the useful device in it.
“Potty” derives from “chamber pot,” a portable toilet people used in times past for doing their business at night.
The room where you can find a toilet and a sink is called a “restroom” or “bathroom” more often in the US than in Britain.