Dun

Dun is a word in Dwarven to call a place:

• Dun Algaz, the mountain pass and mostly abandoned gateway fortress between Loch Modan and the Wetlands. Occupied to some extent by the Dragonmaw orc clan. Dwarven mountaineers protect the upper tunnel to ensure relatively safe travel between the dwarven homelands and Menethil Harbor.
• Dun Argol, the Iron Dwarf fortress in the Grizzly Hills of Northrend.
• Dun Baldar, the Stormpike Expedition's stronghold in northern Alterac Valley. Established to mine and plumb the underexplored caves for relics. The stronghold's presence invited conflict with the Frostwolf clan who had inhabited the valley since the First War.
• Dun Garok, the prominent dwarven fortress under a hill in southeast Hillsbrad. Used to provide protection to Southshore until it fell to the Forsaken with the rest of Hillsbrad. Currently, the fortress is haunted by its fallen defenders.
• Dun Mandarr, a small dwarven base camp near an icy cavern in eastern Winterspring. Overrun by moonkin.
• Dun Modr, the fortified middle-sized dwarven city just south of the Thandol Span that held significant importance in the Second War. Wrested from the Orcish Horde by Stromgarde warriors from Tol Barad, then retaken by the Horde. After the Horde's defeat, the Alliance regained control of the outpost again. Lost to the Dark Iron dwarves somewhere along the line, and now occupied by the Twilight's Hammer cult, with the Alliance (again) working to reclaim the fort.
• Dun Morogh, the hilly, snow-covered valleys south of the Ironforge Mountain. Homeland of the dwarven clans, and constantly threatened by troggs and ice trolls. These lands hold the gates to the capital cities Ironforge and Gnomeregan, the towns of Kharanos, Anvilmar, New Tinkertown and Brewnall Village, the Ironforge Airfield, and several mines, ranches and caves.
• Dun Argath in the Warcraft II demo. Possibly an early name for Dun Modr.
• Dun Kithas in this Warcraft II concept map in the Northeron region.

Dun Niffelem also exists though it is a frost giant town.

• Dun likely comes from a historical use of the word dún/dùn. According to the Wiktionary:
• dún Irish noun 1. fort, fortress; 2. place of refuge, haven; 3. (secure) residence, house; 4. promontory fort, blufffort, fortress [from Old Irish dún fort, fortress, from Proto-Celtic *dūnom stronghold]
• dùn Scottish Gaelic noun 1. heap, mould; 2. fort, fortress, castle; 3. town [from Old Irish dún fort, fortress, from Proto-Celtic *dūnom stronghold]