cannon / canon are similar-sounding terms with different meanings (referred to as homophones). To better understand the differences, see below for definitions, pronunciation guides, and example sentences using each term. 👇
cannon: (noun) a large artillery gun that is usually on wheels. (noun) heavy gun fired from a tank. (noun) (Middle Ages) a cylindrical piece of armor plate to protect the arm. (noun) heavy automatic gun fired from an airplane. (noun) lower part of the leg extending from the hock to the fetlock in hoofed mammals. (verb) make a cannon. (verb) fire a cannon.
canon: (noun) a rule or especially body of rules or principles generally established as valid and fundamental in a field or art or philosophy. (noun) a priest who is a member of a cathedral chapter. (noun) a contrapuntal piece of music in which a melody in one part is imitated exactly in other parts. (noun) a complete list of saints that have been recognized by the Roman Catholic Church. (noun) a collection of books accepted as holy scripture especially the books of the Bible recognized by any Christian church as genuine and inspired.
cannon: k·AE·n·ah·n
canon: k·AE·n·ah·n
(Examples are Wikipedia snippets under the CC ShareAlike 3.0 license. Definitions drawn from WordNet.)