n. A self-evident, undemonstrable, theoretical, and general proposition to which every one who apprehends its meaning must assent.n. Any higher proposition, obtained by generalization and induction from the observation of individual instances; the enunciation of a general fact; an empirical law.n. In logic, a proposition, whether true or false: a use of the term which originated with Zeno the Stoic.n. one of those generalizations of ordinary experience which nobody doubts, and which are soon replaced by scientific formulations, which latter are also, but less properly, termed middle axioms.