John

John is a common slang term for the toilet or bathroom, often used in casual conversations in the United States. The term has been around since at least the early 20th century, and it likely comes from the use of "John" as a common male name, making it a humorous personification of the toilet.

Over time, the term became a staple in everyday language, appearing in books, movies, and TV shows whenever people wanted a polite or funny way to refer to the restroom. While more modern slang for bathrooms exists, like "br" or "porcelain throne," John remains widely recognized and understood.