n. 1. A defensive covering, as of metal, leather, or synthetic materials, worn to protect the body against weapons. 
2. A tough, protective covering, such as the bony scales covering certain animals or the metallic plates on tanks or warships. 
3. A safeguard or protection: faith, the missionary's armor. 
4. a. The combat arm that deploys armored vehicles, such as tanks. 
b. The armored vehicles of an army.