They consists of a number of variables.
- A name, which is not always unique.
- A region to which they belong.
- A 'Terrain block' that is used as the underlying territory.
- A number that determines whether the instance is a staging or a combat area — staging areas are persistent, massively multiplayer, and can have multiple districts; combat areas are instanced and contain only the player characters that entered at creation of the instance.
- A set of objectives in some of them (see mission.)
- A long list of entities that are to 'spawn' in them.
Quests can further affect the entities that spawn.
Refers to moving into a new zone. Rezoning refers to leaving a zone and immediately reentering. This has the following effects:
- Health and energy are fully restored
- Any dead party member or pets are resurrected.
- All bundles are removed.
- Any minions are destroyed.
- Both zones are are recreated (which re-populates foes, redistributes bosses and chests, and resets any unfinished quests).
- All effects (hexes, conditions, etc.) are removed from all characters, with two exceptions:
There are several ways to zone:
- Using a portal, from another zone.
- Via map travel to a town or outpost.
- Through an NPC's dialogue option, which can be used to continue a quest, start a mission, or enter an otherwise restricted area.
- Waiting for a timer to expire, when starting a mission, completing certain missions, defeating a dungeon boss or boss-like foe, or ending a PvP match.
- By using the /resign special command, which, when used by all players in the party, allows the leader to return the party to the last visited outpost/town.
- There are various types of zones
- Staging area - a place you can meet other random players, divided into districts
- Instanced area - a place where your party gets a unique instance of the game
- Explorable area - a map instance where you can kill monsters, vanquish, or complete quests
- Mission area/instance - Some missions have an exclusive map, other missions share the same terrain with explorable areas.
- Quest instance - while most quests simply take place in an explorable area with additional NPC/monster/objects spawned, some quests creates a completely new instance sharing only the terrain of the explorable area (similar to missions).
 "To Zone"
"To zone" means to travel through an area boundary or using the map to go to a new zone. Example: "Everybody ready to zone in?", "Just zone, all the dead players will come back to life." This has the same general meaning as the term rezone, with slightly different usage.