A cannon is any piece of artillery that uses gunpowder or other usually explosive-based propellents to launch a projectile. Cannon vary in caliber, range, mobility, rate of fire, angle of fire, and firepower; different forms of cannon combine and balance these attributes in varying degrees, depending on their intended use on the battlefield. The word cannon is derived from several languages, in which the original definition can usually be translated as tube, cane, or reed. The plural of cannon is cannon, the same word, or more commonly in America, cannons. In modern times, cannon has fallen out of common usage, usually replaced by "guns" or "artillery", if not a more specific term, such as "mortar" or "howitzer". In aviation, 'cannon' remains a common term for aircraft guns.
First used in China, cannon were among the earliest forms of gunpowder artillery, and over time replaced siege engines—among other forms of aging weaponry—on the battlefield. In the Middle East, the first use of the hand cannon is argued to be during the 1260 Battle of Ain Jalut between the Mamluks and Mongols. The first cannon in Europe were probably used in Iberia, during the Reconquista, in the 13th century, and English cannon were first deployed in the Hundred Years' War, at the Battle of Crécy, in 1346. On the African continent, the cannon was first used by the Somali Imam Ahmad ibn Ibrihim al-Ghazi of the Adal Sultanate in his conquest of Ethiopia in 1529. It was during this period, the Middle Ages, that cannon became standardized, and more effective in both the anti-infantry and siege roles. After the Middle Ages most large cannon were abandoned in favor of greater numbers of lighter, more maneuverable pieces. In addition, new technologies and tactics were developed, making most defences obsolete; this led to the construction of star forts, specifically designed to withstand artillery bombardment though these too (along with the Martello Tower) would find themselves rendered obsolete when explosive and armour piercing rounds made even these types of fortifications vulnerable.
Cannon also transformed naval warfare in the early modern period, as European navies took advantage of their firepower. As rifling became commonplace, the accuracy and destructive power of cannon was significantly increased, and they became deadlier than ever, both to infantry who belatedly had to adopt different tactics, and to ships, which had to be armoured. In World War I, the majority of combat fatalities were caused by artillery; they were also used widely in World War II. Most modern cannon are similar to those used in the Second World War, although the importance of the larger caliber weapons has declined with the development of missiles.
In addition to their widespread use in warfare, cannon have found peaceful applications, notably in avalanche control.