Definition of: prime mover

1. An original or chief force in an undertaking.
2. That which is regarded as an original or natural source of the energy required to perform work or develop power, as muscular force, wind, the motion of water, etc.
3. An object or machine used to convert natural forces to productive power, as a turbine, water wheel, windmill, or the like.
4. In Aristotelian philosophy, the first cause of all movement, which does not itself move.