An Armored Combat Vehicle, commonly referred to as a TANK, is a heavily armored military vehicle designed for front-line combat. Tanks are equipped with large caliber guns and other weapons, and are used to break through enemy lines and provide support to infantry units. Tanks are also used in defensive operations, such as providing cover for troops or blocking enemy advances. Tanks have been used in warfare since World War I, and remain an important part of modern militaries.