It’s not, because the x in Linus’ Unix is not referring to the windowing system:
Linux Journal: Is it true that you suggested the name “UNIX” for the long ago OS, Multics? What does that word mean?
Brian Kernighan: Yes, long ago. Multics was an acronym for something like Multiplexed Information and Computing Service, and it was big and complicated because it had many of everything. I suggested Unics for Ken’s new system, because it was small and had at most one of anything. (Multi and uni are both Latin roots, so it was a very weak pun.) Someone else spelled it with the letter X; no one can remember who.
It’s not, because the x in Linus’ Unix is not referring to the windowing system:
https://www.linuxjournal.com/article/7035