5/11/19 CANON & CANNON
  “Canon” used to be such a rare word that there was no temptation to confuse it with “cannon”, which is a large piece of artillery or a large automatic gun that is shot from an aircraft. The debate over the literary canon (a list of officially-approved works) and the popularity of Pachelbel’s Canon (a compositional technique) have changed all that—confusion is rampant. Just remember that the big gun is a “cannon.” All the rest are “canons.” However, note that there are metaphorical uses of “cannon” for objects shaped like large guns, such as a horse’s “cannon bone.” (large metacarpal and large metatarsal).