From WordNet (r) 3.0 (2006) [wn]:
armor
n 1: protective covering made of metal and used in combat [syn:
armor, armour]
2: a military unit consisting of armored fighting vehicles [syn:
armor, armour]
3: tough more-or-less rigid protective covering of an animal or
plant [syn: armor, armour]
v 1: equip with armor [syn: armor, armour]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Armor \Ar"mor\, n. [OE. armure, fr. F. armure, OF. armeure, fr.
L. armatura. See Armature.] [Spelt also armour.]
1. Defensive arms for the body; any clothing or covering worn
to protect one's person in battle.
[1913 Webster]
Note: In English statues, armor is used for the whole
apparatus of war, including offensive as well as
defensive arms. The statues of armor directed what arms
every man should provide.
[1913 Webster]
2. Steel or iron covering, whether of ships or forts,
protecting them from the fire of artillery.
[1913 Webster]
Coat armor, the escutcheon of a person or family, with its
several charges and other furniture, as mantling, crest,
supporters, motto, etc.
Submarine, a water-tight dress or covering for a diver. See
under Submarine.
[1913 Webster]