A mast is a vertical supporting column. The term takes on more specific meaning depending on the context.
A forklift mast is one of many parts that make up the forklift truck frame. It is comprised of metal plates that lift, lower, and tilt materials. The mast has interlocking rails that give it support during its movement of heavy materials. It is made operable with the use of hydraulic cylinders or a series of chains that are linked to the truck’s motor. The mast can be located in the front or the rear of the truck.
Regarding cranes and derricks, a mast is a vertical supporting member. Masts are usually used as a base for which booms and hoists are added. Some masts are able to rotate to swing their boom around.