As a Noun: 1. A device or system which controls the rate at which energy is converted into motion. It usually consists of moving wheels and levers which fit together. English = gears. 2. A piece of equipment which uses electricity or power from an engine, especially one that has gears. English = machine. 3. Part of a machine that uses electricity or fuel to produce movement, so that the machine can work. English = motor, engine. 4. A skilled person who uses scientific knowledge to design and construct machinery, electrical devices, or roads and bridges; the skill itself. English = engineer; engineering. 5. The components of a machine or a collection of machines. English = machinery. As a Verb or Adjective: 1. Of a motor, engine or gears, to turn over, to operate correctly.