The honor system is a way for players to gain honor rewards and PvP rewards by participating in PvP (Player vs. Player) settings (random, world, arena, battleground, or zone). Initially, only random, world and battlegrounds were available, but arena and zone areas where added
There are basically two types of PvP zones: subzones and full zones. They are distinguished from other PvP areas in that special rules and effects apply while in these zones, but they are not instanced in any way, so players can enter and leave the zones freely. World of Warcraft started with PvP tasks in Eastern Plaguelands and Silithus, Burning Crusade added more PvP subzones (in Hellfire Peninsula, Nagrand, Terokkar Forest, and Zangarmarsh), and Wrath of the Lich King added full PvP zones (Wintergrasp).