- A self-evident or universally recognized truth; a maxim.
- An established rule, principle, or law.
- A self-evident principle or one that is accepted as true without proof as the basis for argument; a postulate.
- A self-evident, undemonstrable, theoretical, and general proposition to which every one who apprehends its meaning must assent.
- Any higher proposition, obtained by generalization and induction from the observation of individual instances; the enunciation of a general fact; an empirical law.
- In <em>logic</em>, a proposition, whether true or false: a use of the term which originated with Zeno the Stoic.
- 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 <em>middle axioms.</em>
- A self-evident and necessary truth, or a proposition whose truth is so evident as first sight that no reasoning or demonstration can make it plainer; a proposition which it is necessary to take for granted; as, “The whole is greater than a part;” “A thing can not, at the same time, be and not be.”
- An established principle in some art or science, which, though not a necessary truth, is universally received.
- A seemingly <xref>self-evident</xref> or necessary <xref>truth</xref> which is based on <xref>assumption</xref>; a <xref>principle</xref> or <xref>proposition</xref> which cannot actually be proved or disproved.
- A fundamental <xref>theorem</xref> that serves as a basis for <xref>deduction</xref> of other theorems. Examples: "Through a pair of distinct points there passes exactly one straight line", "All right angles are congruent".
- An established <xref>principle</xref> in some artistic practice or science that is universally received.
- (logic) a proposition that is not susceptible of proof or disproof; its truth is assumed to be self-evident
- a saying that is widely accepted on its own merits