“404” can refer to several things, so I need a little more context to understand what you’re interested in. Here are some possibilities:
HTTP Error Code:
In the world of web browsing, “404” is most commonly known as an HTTP error code. It indicates that the server could not find the requested resource (page, file, etc.) despite a valid request being sent. You might see this message if you:
- Typed the wrong URL
- Followed a broken link
- Tried to access a page that has been removed