1. the practical application of science to commerce or industry
2. the discipline dealing with the art or science of applying scientific knowledge to practical problems
he had trouble deciding which branch of engineering to study
3. a room (as on a ship) in which the engine is located
4. Originally, the art of managing engines; in its modern and extended sense, the art and science by which the mechanical properties of matter are made useful to man in structures and machines; the occupation and work of an engineer.