Canon vs. Cannon: What’s the Difference?

“Canon” and “cannon” are homophones; the two words sound the same though they have different meanings. “Cannon” refers to a big gun. The word may conjure the sound of cannon fire in the American Civil War, but cannons actually date from the 13th century and still have a place in modern warfare. 

On the other hand, a canon is a widely accepted law or a body of written work. Since the word “canon” can be a bit more complicated than the word “cannon”, here are a few examples of ways to use the former word in context:

  • A canon of ethics | Standards of ethical conduct
  • The Western canon | A collection of literary works, including authors like Shakespeare and Socrates, that experts often cite as classics of the Western world
  • The biblical canon | Holy scripture according to church law or Jewish religious tradition

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Since “canon” and “cannon” sound so similar, you may wonder whether they come from the same root word.  

According to the Online Etymology Dictionary, the word “canon” originates from the Greek word kanon, meaning “rule.” That evolved into canonicus, Latin for “according to rule.” With the spread of ecclesiastical law throughout Europe, canonicus found its way into regional languages such as French and English. “Canon,” “canonical,” and “canonize” all entered the English language through this pathway. 

The word “cannon” likely dates back to the Sumerian-Akkadian word for “reed.” This word traveled through the Babylonian-Assyrian language, transforming into the Greek word kanna, meaning cane. The Latin canna retained the same meaning: cane, reed. By the time the word entered Old French in the thirteenth century, as cane, it had taken on a secondary meaning as a spear. A century later, Old Italian and Old French had introduced cannone and canon, respectively, both meaning a large barrel. Around 1400, the word came to refer to the artillery weapon in the English language. The timing corresponded with innovations in gunpowder. As Encyclopædia Britannica notes, “Shortly after 1400, smiths learned to combine the ingredients of gunpowder in water and grind them together as a slurry.” 

Since the Greek word kanon (rule) probably came from the Greek kanna (reed), both “cannon” and “canon” could have originated with the word qanu (reed) in Sumerian-Akkadian. 


Merriam-Webster defines the word “cannon” as both a verb and a noun. As a verb, cannon means, “to discharge cannon.” In addition to a large gun, the noun can also refer to “the part of the leg in which the cannon bone is found” and “a very strong throwing arm.” 

The most common definitions for the word “cannon” involve heavy projectiles or weaponry:

  • A large, carriage-mounted gun
  • An automatic aircraft weapon that uses explosive shells for ammunition 
  • A tool or weapon intended to propel something at high speeds

In contrast, the word “canon” is exclusively used as a noun. It may refer to church dogma or a provision of canonical law. In addition to these meanings, Merriam Webster lists definitions that include, “the most solemn and unvarying part of the Mass including the consecration of the bread and wine” and “a contrapuntal musical composition in which each successively entering voice presents the initial theme usually transformed in a strictly consistent way.” 

Several of the definitions of “canon” pertain to a body of writing or other works:

  • A list of books believed to be Holy Scripture
  • The verified works of a writer
  • A body of works grouped together by tradition

As an alternative definition, the word “canon” may refer to rules and standards. 

  • An accepted rule
  • A criterion for judgment
  • A set of standards, principles, or norms

A canon may also refer to a person or a group of people, especially in a religious vocation. The word can signify “a clergyman belonging to the chapter or the staff of a cathedral or collegiate church” or a canon regular, “a member of one of several Roman Catholic religious institutes of regular priests living in community under a usually Augustinian rule.”


According to, synonyms for cannon include:

  • howitzer
  • mortar
  • ordnance
  • Big Bertha
  • Long Tom
  • heavy artillery lists the following as primary synonyms for canon:

  • precept
  • tenet
  • oeuvre

Other Words and Phrases

Cañon is a variant spelling of the word canyon and describes a distinctive geological formation. The Grand Canyon in Arizona is a famous example. 

Canon Inc. is a Japanese company, listed as (CAJ) on the New York Stock Exchange. The corporation produces optical, imaging, and industrial products, including printers and lenses. 

In English billiards, a cannon is a stroke that involves a cue ball striking the red ball and the opponent’s ball. 

A cannonball can refer to artillery ammunition, but the term also means a splash-producing jump into a swimming pool or another body of water. 

“A loose cannon” signifies someone or something that has become dangerously out of control. Merriam Webster attributes that phrase to American President Theodore Roosevelt, who said that he “[didn’t] want to be the old cannon loose on the deck in the storm.” From that metaphor, the phrase “loose cannon” entered the lexicon. 

“Cannon fodder” describes military troops given dangerous assignments. The phrase implies that someone in leadership decided to classify the soldiers as expendable—as fodder (food) for enemy cannons.