Yeah, I get it. (And why did I think you or someone else was going to be nitpicky and mention that?)
I mention the word "reboot" loosely.
Star Trek rebooted the Star Trek film franchise, which was dead after
Star Trek Nemesis. Yes, it didn't reboot them wholesale narratively speaking, but it was a reboot in concept with a brand new cast, brand new approach to
The Original Series, etc. The "alternate timeline" plot device was a brilliant way to do a clean slate while still honoring what came before.
X-Men: First Class was a "semi-reboot" in the sense that it also brought on new actors, a new setting, and a brand new aesthetic/vibe while still honoring what came before. In a way,
Days of Future Past was a slightly harder reboot because it also erased the previous films, but
First Class felt like a palate cleanser in the sense that Matthew Vaughn brought a James Bond sensibility to an
X-Men film. Studio execs and filmmakers threw about these terms loosely, given that both films essentially restarted both franchises.
I look forward to the upcoming argument discussing the minutiae of why the term "reboot" was "improperly" utilized on my behalf.
EDIT: When I describe
First Class as a "semi-reboot", I am describing it that way because of how I've heard it described elsewhere, i.e.
here,
here, and
here.