Washrooms around the world are called by different names. In the United Kingdom, public toilets are referred to in many ways—some call it a restroom, others call it a loo. However, quite a few public toilets in the island nation are signaled by a “WC” sign, yet apparently very few people know what that actually means. A TikTok user recently responded to a follower who asked what WC stood for, and the clip was viewed over 3,500 times.

The TikToker explained that before indoor plumbing, there was a room for the bathtub—a bathroom. But the water spout was outside, so people had to carry water in with a bucket, heat it up, and pour it into the tub. When indoor plumbing arrived, there was already a room with a bath, so the toilet was simply placed in a closet—the easiest place to put it. The TikToker revealed that WC actually stands for “water closet.”

This revelation led to many discussions, with people expressing surprise even though the sign has been in use since the 1870s. One user wrote, “I’m glad someone asked because I’ve been wondering about this for years but never googled it.” Another commented, “Can’t believe I’ve been living with a WC sign and had no idea why it was called WC.” A third user admitted, “I was 23 when I learned that WC is water closet.”

Other users were surprised that people worldwide didn’t know the full form of the WC sign. One stated, “I’ve known this since I was 13.” Someone else mocked, “Convinced I live in LA because of the common sense levels in the UK, or lack thereof.” Regardless of whether you knew the origin or not, the WC sign remains a classic example of how everyday symbols can carry centuries of history that most people never think to question.