Your armor is the equipment that is equipped in the center-slot of a character's inventory, his torso. These are often the equipment that will provide you a high defense (Armor Value) while compared to the other kinds of equipment, but will probably be the heaviest piece of your set.
However, they are expensive, and you might spend much more money on your armor than on any other equipment piece.
Today, you have 60 armors available in game. The strongest Armor is the Magic Plate Armor (called also MPA), and the strongest available armor which is still obtainable in Rookgaard is the Chain Armor.