To take by the arm; to take up in one's arms.
To supply with armour or (later especially) weapons.
Example: "The king armed his knights with swords and shields."
To prepare a tool or a weapon for action; to activate.
Example: "Remember to arm the alarm system before leaving for work."
To cover or furnish with a plate, or with whatever will add strength, force, security, or efficiency.
Example: "To arm the hit of a sword; to arm a hook in angling"
To furnish with means of defence; to prepare for resistance; to fortify, in a moral sense.
To take up weapons; to arm oneself.
To fit (a magnet) with an armature.