Weapon (noun)

1. An instrument of attack or defense in combat, as a gun, missile, or sword.
2. Any instrument or device for use in attacking, defeating, or injuring an enemy or a target.

Origin:

Middle english: from old northern french, variant of old french wapun, of germanic origin; related to wield.

Examples:

1. The soldier carried a weapon.
2. The weapon of choice for the hunter was a rifle.
3. The weapon was used in the war.
4. The weapon was designed to be used in close combat.
5. The weapon was tested for accuracy.