The difference between Armor and Cavalry

Armor as a noun (uncountable):

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

Armor as a noun (uncountable):

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

Armor as a noun (uncountable):

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

Armor as a noun (countable):

A tank, or other heavy mobile assault vehicle.

Armor as a noun (military, uncountable):

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

Armor 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.

Armor as a verb (transitive):

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

Armor as a verb (transitive):

To provide something with an analogous form of protection.

Cavalry as a noun (military, uncountable):

The military arm of service that fights while riding horses.

Cavalry as a noun (military, countable):

An individual unit of the cavalry arm of service.

Cavalry as a noun (military, countable):

The branch of the military transported by fast light vehicles, also known as mechanized cavalry.