1. Body Part: This is the most common meaning, referring to the upper limb of the human body. This meaning is derived from Old English "earm", which has the same meaning.
2. To Equip: This meaning comes from the Old French "arme", which means "weapon". This sense of "arm" implies providing with weapons or tools to defend or attack.
Examples:
* Body Part: "He broke his arm in the accident."
* To Equip: "The soldiers were armed with rifles."
Keep in mind that these are just the basic meanings. The word "arm" can take on a variety of different meanings in specific contexts. For example, "armchair" is a type of chair, and "armament" refers to a collection of weapons.