It’s an acronym you see everywhere: on restaurant doors, in train stations, hotels, airplanes… Yet, it remains somewhat mysterious to many. What does WC really mean? Why do we use these letters instead of simply saying “toilet” or “bathroom”? Here’s a hint: the answer is more historical (and a little amusing) than you might think.
A little lesson in vintage English: “Water Closet” 
“WC” stands for Water Closet, literally “water closet.” This expression comes from England, from a time when toilets were located in a small, enclosed room, often separate from the bathroom. And since the flush toilet was a fashionable innovation at the end of the 19th century, people referred to it as a closet with water… hence “Water Closet.”