1. (n.) An instrument of offensive of defensive combat; something to fight with; anything used, or designed to be used, in destroying, defeating, or injuring an enemy, as a gun, a sword, etc.

2. (n.) Fig.: The means or instrument with which one contends against another; as, argument was his only weapon.

3. (n.) A thorn, prickle, or sting with which many plants are furnished.