Melee is a categorisation of combat. Melee combat comprises of physical damage caused by hand-held weapons. All classes within Aion are capable of inflicting melee damage, but only the Gladiator and Templar are specialised with this type of combat.
Melee damage can be mitigated by the use of Skills, potions, spells or by wearing armour. Plate armour is the most defensive when fighting a melee specialised class, with Chainmail being the next powerful, followed by Leather and finally Cloth.