quadraginta
Becoming Beth
I suppose if we use the word to mean minority of power, or something to that effect, it makes sense. But that's not how I understand the term.
Yes. Because there is only one possible common meaning for any common term.
Outside the hallowed halls of Internet Pedantry™, though, there is often more than one common usage for common terms, such usage generally quite easily discerned through context.
Since you have been somehow left bereft of the knowledge, here is a wiki article which may be of help.