Armor is protective wear. Armor mitigates physical damage; it does not make you harder to hit. Shields are an exception, they make you harder to hit and offer additional protection against missile hits. Armor in Dragon Age: Origins does not degrade and can be crafted from a variety of mystical and mundane materials.
There are four types of armor: massive armor, heavy armor, medium armor, and light armor. To use armor, a character must meet a minimum strength requirement. Armor is not limited by race or class, but some special armors are only usable by specific specializations.
Collars and Kaddis are the upgrade slots for the dog follower and have armor-like properties.
Armor comes in the form of body armor, boots, gloves, helmets, and shields. Having the matching set of gloves, boots, and armor of a given set provides additional bonuses, as entire set that was designed to be used together is more effective than mix and match.
The Dreadnaught armor was called the 'most powerful armor in the game' by Chris Priestly.
Examples of Armor
Blood Dragon Armor
Havard’s Aegis shield - +4% spell resistance, chance to avoid missile attacks