An axiom.
true
An axiom.
It is called an axiom.
An axiom.
A rule or a statement that is accepted without proof is a postulate.
A statement accepted without proof is commonly known as a theorem. The other word that is used for such statements is postulate.
postulate
a
axiom
A postulate
An axiom.
true
An axiom.
accepted as true without proof
A postulate or axiom
An axiom.