# Axiom

An axiom, postulate, or assumption is a statement that is taken to be true, to serve as a premise or starting point for further reasoning and arguments. The word comes from the Ancient Greek word ἀξίωμα, meaning 'that which is thought worthy or fit' or 'that which commends itself as evident'. The precise definition varies across fields of study. In classic philosophy, an axiom is a statement that is so evident or well-established, that it is accepted without controversy or question. In modern logic, an axiom is a premise or starting point for reasoning. In mathematics, an axiom may be a "logical axiom" or a "non-logical axioms". Logical axioms are taken to be true within the system of logic they define and are often shown in symbolic form, while non-logical axioms are substantive assertions about the elements of the domain of a specific mathematical theory, such as arithmetic. Non-logical axioms may also be called "postulates" or "assumptions".