engine meaning and definition

ENGINE noun

Definition of engine (noun)

1. motor that converts thermal energy to mechanical work
2. something used to achieve a purpose
   • "an engine of change"
3. a wheeled vehicle consisting of a self-propelled engine that is used to draw trains along railway tracks
   • synonyms: locomotive, locomotive engine, railway locomotive
4. an instrument or machine that is used in warfare, such as a battering ram, catapult, artillery piece, etc.
   • "medieval engines of war"