I just added a tag for fare-class since I saw a question about them and thought it's a frequent enough topic in air travel even though I didn't know exactly what it was.
I guess it's something more technical used by airlines but only pretty savvy fliers really know properly.
I tried to look it up on Wikipedia but there's no article on it though it is used in other articles. Google instead offered me two Wikipedia articles, Fare basis code and Travel class one of which is probably another word for the same thing, but I'm still not sure, so why not ask a bunch of experts like all of you?
My guess is it's the former and that non savvy fliers would kind of assume that it's the latter but is actually more technical?