a large artillery gun that is usually on wheels
"The ancient battlefield was dominated by rows of massive cannons rolling forward to fire at the enemy lines."
heavy gun fired from a tank
"The tank's main cannon easily destroyed the enemy bunker at long range."
(Middle Ages) a cylindrical piece of armor plate to protect the arm
"The knight slid his armored cannon over his forearm before gripping the sword hilt."
heavy automatic gun fired from an airplane
"The fighter jet released its cannon to destroy the enemy tanks below."
A complete assembly, consisting of an artillery tube and a breech mechanism, firing mechanism or base cap, which is a component of a gun, howitzer or mortar. It may include muzzle appendages.
"The maintenance crew inspected the entire cannon to ensure the artillery tube, breech mechanism, and base plate were securely assembled before deployment."
In plain English: A cannon is a large gun used by armies to shoot powerful shells over long distances.
"The big cannon on top of the castle tower pointed down at the field below."
Usage: Use this word to refer specifically to the heavy military weapon itself rather than its projectile. It describes the entire assembled piece used for launching shells in warfare contexts.
make a cannon
"The blacksmith spent months forging and assembling the heavy iron barrel to finally make a cannon ready for battle."
To bombard with cannons.
"The enemy army decided to cannon the coastal fortress until it surrendered."
A surname.
"The famous jazz musician Cannonball Adderley performed at the festival under his stage name, but he was also known by his birth name, Lloyd Parks, while his father's family used the surname Cannon."
The word "cannon" entered English around 1400 via the Old French canon and Italian *cannone, originally referring to a large reed before evolving to mean a long tube for firing projectiles. This term traces its roots back through Latin and Ancient Greek to Akkadian and Sumerian words meaning "reed."