a device for lifting heavy loads

The arm of a mechanical crane.

a crane-like device (usually one of a pair) for suspending or lowering equipment (as a lifeboat)

a simple crane having lifting tackle slung from a boom

a crane for moving material with dispatch as in loading and unloading ships

a crane with a forklift type mechanism used in automated (computer controlled) warehouses (known as an automated storage and retrieval system).

a type of large dockside gantry crane found at container terminals for loading and unloading intermodal containers from container ships.