Washrooms around the world are called by many different names. Whether it’s “bathroom,” “restroom,” or the ever-polite “lavatory,” every country seems to have its preferred terminology. One country that boasts a rich variety of names for public toilets is the United Kingdom. Here, you might hear people say “restroom,” “loo,” or even “lav.” However, there’s another term often seen in public spaces that has left many scratching their heads: the WC sign.

Despite the fact that the WC sign has been in use for over a century, many people still don’t know what it stands for. If it wasn’t for a TikTok user who recently enlightened the world, some of us might have never figured it out.

The Revelation Behind the WC Sign

A TikTok video that’s gone viral (with over 3,500 views) has finally shed light on this mysterious sign. In the clip, TikToker @itsnathannyc explains the meaning behind WC, responding to a follower’s inquiry. The answer? WC stands for Water Closet—a term that has been in use since the 19th century.

Before modern indoor plumbing, homes had a separate room for bathing, but the water source was often outside. People would heat water manually and pour it into a bathtub. Once plumbing arrived, there was already a room called the bathroom for bathing, so when it came time to install a toilet, people needed a new term. Thus, the “water closet” (or WC) was born—essentially a small, enclosed space where the toilet was installed, hence the name closet.

A Surprising Revelation

Although the WC sign has been used for nearly 150 years, many people were surprised to learn its true meaning. Comments poured in on TikTok, with many users admitting they had never bothered to look it up. One user said, “I’m glad someone asked because I’ve been wondering about this for years but never googled it.” Another confessed, “Can’t believe I’ve been living with a WC sign and had no idea why it was called WC.”