Armor is material protection against damage. It ranges in size from personal body armor to the thick metal protection of battleships. Armor typically functions by being sturdy enough to withstand impacts or energy without being deformed, although ablative armor specifically works by being destroyed instead of whatever it protects.
Armor is often a design characteristic of military vehicles. The effectiveness of armor depends on the strength of suitable materials relative to the destructive power of weapons likely to be used against it.
In science fiction, armor is often replaced or supplemented by shields.