The letters “WC” on bathroom signs stand for “Water Closet,” an old-fashioned term for a toilet room. Originally, a water closet was a separate small room specifically for the toilet, dating back to times when bathing was done in a different space. As indoor plumbing became common in the 19th and early 20th centuries, the term spread worldwide and became a familiar label especially in airports, hotels, and public places—though it can still confuse people unfamiliar with it.

In 2020, a TikTok video by Shelby and Dylan humorously questioned common terms like “washroom” and “restroom,” asking if anyone actually rests or washes in these rooms. The video went viral, sparking playful debates online about the many names people use for the bathroom. Depending on where you live, you might say “bathroom,” “washroom,” “toilet,” or “WC.”

Regional differences are common: In Canada, “washroom” is the preferred term, while in the U.S., people usually say “bathroom” or “restroom” depending on the area. Other countries have their own unique names, like in Russia, where the bathroom is sometimes called a “room without windows.” Reddit users have also discussed the confusing “closet” part of “Water Closet,” sharing laughs and stories about the term.

Despite the different names and histories, all these terms refer to the same basic function: a room for using the toilet. So whether you see “WC” on a sign or hear someone say “restroom,” you know exactly where to go.