An armour (British English) or armor (American English; see spelling differences) is a protective covering that is used to prevent damage from being inflicted to an object, individual or vehicle by direct contact weapons or projectiles, usually during combat, or from damage caused by a potentially dangerous environment or action (e.g., cycling, construction sites, etc.). Personal armour is used to protect soldiers and war animals. Vehicle armour is used on warships and armoured fighting vehicles.
A second use of the term armour describes armoured forces, armoured weapons, and their role in combat. After the evolution of armoured warfare, mechanised infantry and their weapons came to be referred to collectively as "armour".
The word "armour" began to appear in the Middle Ages as a derivative of Old French. It is dated from 1297 as a "mail, defensive covering worn in combat". The word originates from the Old French armure, itself derived from the Latin armatura meaning "arms and/or equipment", with the root armare meaning "arms or gear".
Armour has been used throughout recorded history. It has been made from a variety of materials, beginning with rudimentary leather protection and evolving through mail and metal plate into today's modern composites. For much of military history the manufacture of metal personal armour has dominated the technology and employment of armour. Armour drove the development of many important technologies of the Ancient World, including wood lamination, mining, metal refining, vehicle manufacture, leather processing, and later decorative metal working. Its production was influential in the industrial revolution, and furthered commercial development of metallurgy and engineering. Armour was the single most influential factor in the development of firearms, which in turn revolutionised warfare.