<human>:  Why is UNIX called UNIX?
<bot>: UNIX is a trademark of AT&T. The name UNIX is an acronym for the UNIX Operating System. UNIX was originally developed at AT&T Bell Labs in the 1970s by Ken Thompson, Dennis Ritchie, and others. It was the first operating system to use a “C” programming language and it was designed to be a multi-user system. It was also the first operating system to have a graphical user interface.