Q: Three “cannon” or three “cannons”? Is this a uniquely UK English problem?
A: The answer is yes. After checking ten standard British and American dictionaries, we can safely say that the plural of “cannon” is a bone of contention only in the UK.
In the US, this noun has two plurals and you’re free to use either one—“cannons” or the collective noun “cannon.” All five standard American dictionaries agree.
But opinion in the UK is mixed. Three of the British dictionaries list only “cannons” as the plural, and the two that do include “cannon” differ about the usage—one say it’s “mainly UK,” the other says it’s American.
Our advice? If you live in the US, either plural will do. If you live in the UK and you want to be in the majority, use “cannons.”
The Oxford English Dictionary, an etymological dictionary based on historical records, has plenty of evidence for both plural forms—“cannons” (dating from the 15th century) and “cannon” (from the 16th). But Oxford doesn’t say which is more common in the US or the UK.
As for its etymology, “cannon” is a relative of the word “cane” (as in sugar cane), and its name comes from the gun barrel’s resemblance to a hollow reed.
The noun came into English in the 1400s from Anglo-Norman and Old French (canon), in which it meant a pipe, tube, or artillery piece, the OED says.
Earlier ancestors were the Old French cane (hollow reed) and the Italian cannone (organ pipe, reed, tubular object), both from the Latin canna (a hollow reed or cane).
The Romans acquired canna from the Greek κάννα (kanna, reed), and the OED says it “perhaps” can be traced even farther back to Hebrew and Arabic, which have similar words.
From the beginning, however, “cannon” in English meant the big gun. The OED defines it this way: “A large, heavy piece of artillery formerly used in warfare, typically one requiring to be mounted for firing, usually on a wheeled carriage; now chiefly used for signaling, ceremonies, or re-enactment.”
The oldest recorded examples of the noun are in the plural. Oxford’s earliest citation is from a work on the art of war written in the late Middle Ages, in the days when cannons shot projectiles of lead, iron, or stone:
“The canonys … bloweth out … stonys grete” (“The cannons … shoot out … great stones”). From Knyghthode and Bataile (circa 1460), an anonymous Middle English work that rewrites, paraphrases, and puts into verse a fourth-century Latin book on war, De re Militari, by Publius Vegetius Renatus.
The modern spelling first appeared in the 16th century in the state papers of King Henry VIII. These are the OED citations, which treat the word as an ordinary noun (singular “cannon,” plural “cannons”):
“5 gret gonnes of brasse called cannons, besides sondery [sundry] other fawcons [small cannons]” (1525) … “To sende unto Tynmowthe … a cannon, a saker [light cannon], etc.” (1545).
(A note of explanation. Old ballistic weapons were often named after birds of prey or venomous snakes, and the passages just quoted mention some of these: the “falcon,” spelled “fawcon” above; the “saker,” for the lanner falcon or Falco sacer; and the “basilisk” and “culverin,” both serpents. This naming practice also accounts for “musket,” an archaic word for a sparrowhawk.)
The collective use—the plural without the “s”—was first recorded, the OED says, in Shakespeare’s Henry IV, Part 1 (1598), though with the French spelling: “Thou hast talkt … Of basilisks, of canon, culuerin.”
Examples of both plurals, “cannons” and “cannon,” are common from the 1600s onward. Here are the most recent OED citations for each:
“I got to walk around one battlefield after another, posing for pictures with cannons and Colonial reenactors” (from The Darkest Minds, a 2012 novel by Alexandra Bracken).
“There’s definitely a regiment readying to move out. They’ve got supply wagons and cannon lined up” (from Madness in Solidar, a 2015 novel by L. E. Modesitt Jr.).
Perhaps the most memorable use of “cannon” in the plural is from Tennyson’s poem The Charge of the Light Brigade (1854), in which you can almost hear the galloping hoofs: “Cannon to right of them, / Cannon to left of them, / Cannon in front them / Volley’d and thunder’d.”
Jeremy Butterfield, in Fowler’s Dictionary of Modern English Usage (4th ed.), quotes the poem to illustrate the use of “cannon” as a collective noun. He notes that historically, the word has been used both ways—“as an ordinary noun, with plural cannons; but also collectively.”