I don't define axioms. It is the general definition commonly used, as recorded (but not decided) by the dictionary. Do you in fact have a different definition?
They have the actual meaning that the majority or community gives them. But that isn't necessarily static. But you've shown no evidence that it's changed in this case. That's what I've always been saying.
What do you mean settled? Do words meaning change? Absolutely. Quick examples from Google are awesome, egregious, awful, terrific, smeart->smart, nice, wicked, presently, etc