Have you ever wondered what “XP” stands for or where “Ubuntu” comes from? Some operating systems get their names from obvious places, but others need some explaining. Read on to find out where your favorite OS got its name.

We’ve rounded up the most popular and well-known operating systems, as well as a few lesser-known ones—if you know of another operating system with an interesting story behind its name, make sure to teach your fellow readers in the comments.