canon

\ \ There are today two distinct words canon in English, although ultimately they are related.

\ \ The older, ‘(ecclesiastical) rule’ [OE], comes via Latin canōn from Greek kanón ‘rule’, which some have speculated may be related to Greek kánnā ‘reed’, source of English cane (the semantic link is said to be ‘reed’ – ‘rod’ – ‘measuring rod’ – ‘rule’). The derived adjective, kanonikós, passed into ecclesiastical Latin as canonicus, which was used as a noun, ‘clergyman’; in Old French this became canonie or chanonie, and as it crossed into English its last syllable dropped off (owing to the influence of canon ‘rule’). The underlying sense of canon ‘clergyman’ [13] is thus ‘one living according to the rules of religious life’.