Loo. Despite being a very British word for toilet, 'loo' is actually derived from the French phrase 'guardez l'eau', which means 'watch out for the water'. ... Over time, it became loo and was applied to the toilet itself.

Is loo a slang word?

“Loo” is, of course, slang, primarily British, for the toilet, restroom or bathroom (or whatever your favorite euphemism might be). The origin of “loo” has been hotly, and often quite creatively, debated since the word first appeared.

Is a bathroom called a loo?

When people flung their potty waste out of the window, they would shout “Gardez l'eau” [gar-day low]. That's French for “watch out for the water”. We probably get the word “loo” from this expression, although some people think it comes from “Room 100” which is what European people used to call the bathroom.