prime mover(redirected from a prime mover)
Fig. the force that sets something going; someone or something that starts something off. The assistant manager was the prime mover in getting the manager sacked. Discontent with his job was the prime mover in John's deciding to retire early.
The initial source of energy directed toward a goal, someone or something that sets others in motion. For example, Jean was the prime mover in getting us more laboratory space, or Patriotism was the prime mover of the revolution. [Late 1600s]