weap·on 
(wĕpən)
(wĕpən)n.
1. An instrument of attack or defense in combat, as a gun, missile, or sword.
2. Zoology A part or organ, such as a claw or stinger, used by an animal in attack or defense.
3. A means used to defend against or defeat another: Logic was her weapon.
tr.v. weap·oned, weap·on·ing, weap·ons
To supply with weapons or a weapon; arm.
[Middle English wepen, from Old English wǣpen.]