canon
A generally accepted principle; a rule.
Example
“The trial must proceed according to the canons of law.”
Other meanings
artistic A formally codified set of criteria deemed mandatory for a particular artistic style of figurative art.
literary A group of literary works that are generally accepted as representing a field.
Word history
From Ancient Greek "κανών" (measuring rod, standard).
Where this comes from
This definition is adapted from “canon” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.