A broad and basic rule or truth
A proposition assumed to be true
You cannot keep using that unproven axiom as the basis for your paper.
This mechanical axiom of the normality of fluid pressure is the foundation of the mathematical theory of hydrostatics.
Many people believe the axiom that "people cannot change", and thus have little faith in humanity.
But in his successors, from Fichte to Hegel, this axiom of the plain man is set aside as antiquated.
It became an axiom that the law of the king's court stood above all other law and was the same for all.