PowerPlant is an object-oriented GUI toolkit, application framework and set of class libraries for Mac OS, created by Metrowerks. The framework was fairly popular during the late (OS versions 8 and 9) Classic Mac OS era, and was primarily used with CodeWarrior. It was designed to work with a GUI editor called Constructor, which was primarily a resource editor specializing in UI elements. Constructor used several custom resource types, 'PPob' ("PowerPlant object"—a general view description), 'CTYP' (custom widgets), and Mcmd (used for dispatching menu-related events).

Propulsion is a means of creating force leading to movement. The term is derived from two Latin words: , meaning after or forward; and , meaning to drive. A propulsion system consists of a source of mechanical power, and a propulsor (means of converting this power into propulsive force).