The Joule is the SI unit for energy.  It has the symbol J.

One Joule is equal to the work done on (or energy transferred to) an object when a force of one Newton acts on that object in the direction of the force’s motion through a distance of one metre.  It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second.  It is named after the late English physicist James Prescott Joule.