- An engine (or motor) is a machine designed to convert one or more forms of energy into mechanical energy
- A heat engine is a type of engine that converts heat energy into mechanical energy
- An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit
- A heat engine is a type of engine that converts heat energy into mechanical energy