I thought Linus wanted to call it FREAX and others involved in the project insisted on Linux?
Anyway - I don't know if you're familiar with the FreeDOS project but Linux is to Unix as FreeDOS is to DOS, sort of. One is a closed source (nominally) and licensed-for-a-cost system and one is open source and basically free.
The Linux kernel is assembled with GNU utilities and GNU stands for GNU's Not Unix - cuz it isn't Unix (proprietary) but it is Unix (looks like a Unix, quacks like a Unix - it's a Unix).
That's why you'll see '*nix' a lot. Given, POSIX, it might even be better to say '*ix" except it sounds funny.
There are a lot of *nixes and Linux is one of them, but it isn't Unix.
And everybody should read The Cathedral and the Bazaar just because. *g*