You’ve seen it on doors from Paris to Bangkok — that simple, unassuming “WC” sign pointing you toward the nearest restroom. It’s one of the most universally recognized signs in the world, yet most people who walk past it every day couldn’t tell you what the letters stand for.

The Answer: Water Closet

 WC stands for Water Closet — an old British term for a small  room containing a flush  toilet. The phrase dates back to the late 1800s, when indoor plumbing and flush toilets were a genuine novelty. Before that, most people used outhouses or chamber pots, so a “closet” (a small enclosed room) with running water for flushing was a distinct and notable feature worth naming