Engery is measured in unit called?

The unit is called Joule. The reason why this is the case is because Energy is defined by work, so the SI unit for Energy is the same as the SI unit for Work. The Joule, whose name comes from James Prescott Joule who did experiments on the mechanical equivalent of heat. 1 Joule is equal to 1 newton meter. Another Energy unit used in Atomic and Energy Physics is the electronvolt (eV), which is equal to 1.60217653 x 10-19 J.