The word 'rustning' does not have a direct definition in English as it appears to be a Swedish or Norwegian term for 'armor' or 'armament'. In English, it refers to protective covering used to prevent damage from being inflicted to an object, individual, or vehicle by direct contact weapons or projectiles, usually during combat, or to the process of equipping or supplying with weapons. noun
The knight donned his rustning before heading into battle.
The museum displayed an ancient rustning used by medieval warriors.