Websters Dictionary Defines energy as:

• Internal or inherent power, capacity of acting, operating, or producing an effect, whether exerted or not. The great energies of nature are known to us only by their effects. - Paley.
• Power efficiently and forcibly exerted.
• The available kinetic energy of a material system unconnected with any other system is that energy which is due to the motions of the parts of the system relative to its center of mass.

The potential energy of a body or system is that energy which is not kinetic; - energy due to configuration. Kinetic energy is sometimes called ‘actual energy’. Kinetic energy is exemplified in the vis viva of moving bodies, in heat, electric currents, etc, and the potential energy of any mass at a given distance above the earth and acted on by gravity. The kinetic energy of a mass is the energy it has in virtue of being in motion. It is measured by one half of the product of the mass of each element of the mass multiplied by the square of the velocity of the element, relative to some given body or point.