The difference between Armour and Chain mail

Armour as a noun (uncountable):

A protective layer over a body, vehicle, or other object intended to deflect or diffuse damaging forces.

Armour as a noun (uncountable):

A natural form of this kind of protection on an animal's body.

Armour as a noun (uncountable):

Metal plate, protecting a ship, military vehicle, or aircraft.

Armour as a noun (countable):

A tank, or other heavy mobile assault vehicle.

Armour as a noun (military, uncountable):

A military formation consisting primarily of tanks or other armoured fighting vehicles, collectively.

Armour as a noun (hydrology, uncountable):

The naturally occurring surface of pebbles, rocks or boulders that line the bed of a waterway or beach and provide protection against erosion.

Armour as a verb (transitive):

To equip something with armour or a protective coating or hardening.

Armour as a verb (transitive):

To provide something with an analogous form of protection.

Chain mail as a noun:

A flexible defensive armor, made of a mesh of interlinked metal rings.

Chain mail as a noun (sometimes, collectively):

Chain letters.