What does Unix stands for?
Well, Unix is not an acronym. The history of UNIX goes back in time to 1969, when Ken Thompson, Dennis Ritchie and others started working on PDP-7 at Bell Labs.
Multics is a large multi-user operating system that was being developed at Bell Labs shortly before Unix was created in the early ‘70s.
“The number of UNIX installations has grown to 10, with more expected…” Dennis Ritchie and Ken Thompson, June 1972.
In 1970, Peter Neumann coined the project name UNICS (UNiplexed Information and Computing Service). Doug McIlroy attributes UNIX name to Brian W. Kernighan. And the rest is the history.