In thermoynamics, motive power is an agency, as water or steam, used to impart motion. Generally, motive power is defined as a natural agent, as water, steam, wind, electricity, etc., used to impart motion to machinery; a motor; a mover. The term may also define something, as a locomotive or a motor, which provides motive power to a system. In current use, motive power may be thought of as a synonym for either "work", i.e. force times distance, or "power", an effect producing motion, dependending on the context of the discussion.