Public toilets go by many names, but the ‘WC’ sign has puzzled many. People are now realizing what it actually stands for.

The internet often reveals surprising facts, from the purpose of shopping cart hooks to the meaning behind M&Ms. Now, it’s toilets making headlines. One user admitted, “I’m glad someone asked because I’ve been wondering this for years but never googled it.” Another wrote, “Can’t believe I’ve been living with a WC sign and had no idea why it was called WC.” Others, however, were shocked, with one saying, “What?! Who doesn’t know this?”

Historically, when indoor plumbing became common, people converted small closets into toilet rooms, since they were one of the few spaces with running water. A TikToker explained, “Before indoor plumbing, we actually had a room for the bathtub, a bathroom… Indoor plumbing comes along, and the easiest place to put a toilet was in a closet.”

Thus, ‘WC’ stands for ‘water closet,’ a term from the 1900s for a toilet. Plumb World confirms, “Over time, WC has been used instead of bathroom to describe a room with a toilet but no bath.”