Etymology: Found in Old English as canon , < Latin canon rule, < Greek κανών rule. Early Middle English had ˈcanon , probably < Old English, and caˈnun , caˈnoun , < Old French canun , canon , the French descendant of the Latin. Senses 12 – 14 are of obscure origin; some or all may belong to cannon n.¹ in French spelt canon.

Etymology: Found in Old English in the form canonic , < Latin canonicus , a late Latin noun use of the adjective canonicus canonic adj. and n. < canōn , rule, etc.: see canon n.¹ Latin canonicus gave Italian canonico , Spanish canonigo , Provençal canorgue . Catalan canonge , Provençal canonge , Old Northern French caˈnonie , later caˈnoine , central French chanoine , derive from a late Latin form *canonius : compare canonia in Du Cange. The 12th cent. English form was caˈnun , later Middle English caˈnoun : apparently an adaptation of the Old Northern French canonie /kaˈnonjə/, with the ending imperfectly represented (perhaps by confusing with canon n.¹). When this was subsequently influenced by French of Paris, the central French chanoine was represented in English by chanun , chanoun , so common in 14–15th cent. But canon reappeared in the 16th cent. and is the surviving form, running together with the preceding canon n.¹, so that many dictionaries treat the two as one word.

Etymology: < canon n.¹ 7.