can·on 1 
(kănən)
(kănən)n.
1. An ecclesiastical law or code of laws established by a church council.
2. A secular law, rule, or code of law.
3.
a. An established principle: the canons of polite society.
b. A basis for judgment; a standard or criterion.
4. The books of the Bible officially accepted as Holy Scripture.
5.
a. A group of literary works that are generally accepted as representing a field: "the durable canon of American short fiction" (William Styron).
b. The works of a writer that have been accepted as authentic: the entire Shakespeare canon.
c. Material considered to be officially part of a fictional universe or considered to fit within the history established by a fictional universe: "The Harry Potter series was one of the first pieces of media to inspire widespread fan fiction writing, probably because its popularity coincided with the early days of the Internet, but its creator has also shown herself more than willing to keep updating the canon" (Emma Cueto).
6. Canon The part of the Mass beginning after the Preface and Sanctus and ending just before the Lord's Prayer.
7. The calendar of saints accepted by the Roman Catholic Church.
8. Music A composition or passage in which a melody is imitated by one or more voices at fixed intervals of pitch and time.
[Middle English canoun, from Old English canon and from Old French, both from Latin canōn, rule, from Greek kanōn, measuring rod, rule, of Semitic origin; see qnw in the Appendix of Semitic roots.]