armor

Short definition from Wiktionary

Noun

1. 1
   A protective layer over a body, vehicle, or other object intended to deflect or diffuse damaging forces.
2. 2
   A natural form of this kind of protection on an animal's body.
3. 3
   A metal plate, protecting a ship, military vehicle, or aircraft.
4. 4
   A tank, or other heavy mobile assault vehicle.
5. 5
   A military formation consisting primarily of tanks or other armoured fighting vehicles, collectively.
6. 6
   The naturally occurring surface of pebbles, rocks or boulders that line the bed of a waterway or beach and provide protection against erosion.

Verb

1. 1
   To equip something with armor or a protective coating or hardening.
2. 2
   To provide something with an analogous form of protection.

Proper noun

1. 1
   A surname.