Zone

Zones are areas of the map with designated themes, mobs, and scenery. These areas have borders much like a state or country, and though invisible, they define areas. They may contain subzones, cities, towns, villages, or instances. For example, the zone of Dun Morogh contains the subzone of Coldridge Valley, the city Ironforge, the town Kharanos, and the instance Gnomeregan.

In lore, novels, the RPG, the official web site, a zone is usually referred to as a region. However, the community has practically adopted the term 'zone' for any reference to the game itself. Furthermore, lore regions and in-game zones do not always match up (what may be a region in lore may be reduced to a subzone in-game, or some subregions may become their own zones).

Various editions of World of Warcraft Guide also described regions major tracts of land within Kalimdor (Northern, Central, and Southern) or the Eastern Kingdoms (Lordaeron, Khaz Modan, etc.); and divided these regions into a varying amount of zones.

Zones in World of Warcraft
The exterior open world of World of Warcraft currently consists of 10 multi-zone continents and worlds: Argus, the Broken Isles,, the Eastern Kingdoms, Kalimdor, Kul Tiras, Northrend, Outland, Pandaria, and Zandalar, and a number of single-zone areas: Deepholm, Helheim, Molten Front, and Nazjatar. Some zones have different phased versions that can be accessed by Zidormi. Another multi-zone location is being added in the future the Shadowlands.

Additionally a number of zones are only accessible in specific circumstances: Darkmoon Island is accessible 1 week each month, goblin, pandaren and demon hunter starting zones are accessible in their starting experience, the Maelstrom in a quest to Deepholm, unique Class Hall zones accessible only by a specific class, and Blackrock Depths and Telogrus Rift are open world areas only for their respective allied races.