A mortar is a large Gun which fires low velocity, high-arching explosive shells. Only two known types are usable by players: Portable Bronze Mortar (a consumable) and Goblin Mortar (a trinket). Both are made by engineers with the appropriate recipe. Goblin engineers can get a recipe to reload the Goblin Mortar with 6 charges.
They were used extensively as siege weapons by the Alliance during the Third War. Mortars are used by the Dwarven armies of Khaz Modan as a mobile form of artillery, when cannons simply cannot be rolled in. Dwarven Mortar teams consist of a carrier/gunner and a spotter/loader. They are well known for their battlecry, "MORTAR COMBAT!" (a reference to Mortal Kombat, and their advice to targets within earshot: "Hey, you! Catch!" From the time the dwarves first learned to use mortars to the present day, there have been only 3 reported cases of the enemy being stupid enough to actually try catching the shell, with a successful catch being made only once. The name of the individual who performed this impressive feat has been lost, along with most of his anatomy and all insect and plant life in a 15-foot radius of the place where he was standing.