I recently acquired "The Shorter Oxford English Dictionary" on my Ipad. A fanfiction writer asked me what canon was, and unable to cut and paste the definition from my I-Pad, I painstakingly typed it out. Given that this took a little time, I did not want the work to be wasted. So here is the definition of canon.
noun1. Old English
[origin: Latin from Greek kanōn rule: reinforced in Middle English by Anglo-Norman canum, Old French & Modern French canon.]
1. An ecclesiastical law or decree; especially a rule laid down by an ecclesiastical council; singular & usually place canon law. OE
Shakespeare. All's Well That End's Well: Self-love... the most inhibited sin in the canon.
2. The part of the Mass containing the words of consecration. Middle English
3. A general law, rule, or edict; a fundamental principal.
-b Math. A general rule, formula, or table.
-c standard of judgement; a criterion
D. Carnegie "I violated all the canons of courtesy, ignored everyone else." J.K. Galbraith "The balanced budget, so long a canon of the conventional wisdom."
(-c) G. Murray "We are establishing a new conventional canon of what is poetical and what not.
4. Those biblical books officially accepted by any of the Christian Churches as genuinely inspired; any collection or list of sacred works accepted as genuine.
-b A list or catalogue of recognized saints.
-c A list of the recognised genuine works of a particular author, composer, etc.
-d A list of literary works considered to be permanently established as being of the highest quality.
(-c)D. Lodge "A series of commentaries on Jane Austen which would work through the whole canon, one novel at a time."
(-d) F. Kermode "Authority has invented many myths for the protection of the canon.
5. Music. (The style of) of a composition in which different parts take up the same subject successively in strict imitation.
6. Law. A customary payment made to the Church; a quit-rent. Now rare or obsolete.
7. A former size of type equal to four-line pica.
8. [Probably a different word: cf. cannon noun2.] A metal loop at the top of a bell, by which it is hung. Usually in place of crossed loops.
9. (A period or era serving as) a basis for chronology.