Cannon is a powerful, tube-shaped gun that is too large to be carried by hand. The big guns now classed as artillery and the larger guns fired from World War II airplanes were once called cannon. Cannon comes from the Latin word canna, meaning a tube or reed. Large cannons were first used in warfare about 1350. Cannons of this time were cast of bronze and of wrought iron. Cannons firing heavy balls were used extensively in the American Civil War (1861-1865).