WordWeb Online

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
   - locomotive, locomotive engine, railway locomotive [Brit, Cdn], loco [informal], railroad locomotive [N. Amer]
    
4. An instrument or machine that is used in warfare, such as a battering ram, catapult, artillery piece, etc.
   "medieval engines of war"

Derived forms: engines

Type of: causal agency, causal agent, cause, instrument, motor, self-propelled vehicle

Part of: railroad train [N. Amer], railway train [Brit, Cdn], train

Encyclopedia: Engine