Engine/ˈendʒɪn/ Definition 1 of 4Pro Tip 1/3Physical Object Engine refers to a tangible, mechanical item; generally substantial and complex. The mechanic fixed the engine. Pro Tip 2/3Source of Power The word engine suggests being a primary source of power in devices like cars or lawnmowers. The engineer is designing a new engine. Pro Tip 3/3Associated Sounds Engines are often associated with noise; different types have distinct sounds. The engine roared to life.