A tank is a tracked, armored fighting vehicle designed for front-line combat which combines operational mobility and tactical offensive and defensive capabilities.
Firepower is normally provided by a large-caliber main gun in a rotating turret and secondary machine guns, while heavy armor and all-terrain mobility provide protection for the tank and it's crew, allowing it to perform all primary tasks of the armored troops on the battlefield.
Tanks are very lethal war machinery and can surely make a difference when it comes to the battle field. Tanks can both generate a very powerful attack and a strong shield against several enemies attack and can be the difference between life and death.
Tanks were originally called tanks as a way of misleading the enemy into thinking they were water tanks shipped to areas of the battle where water was scarce. This way the enemy suffered the element of surprise!