Energy

Energy is the quantitative property that is transferred to a body or to a physical system, recognizable in the capacity to do work and in the form of heat and light. Energy is a conserved quantity—the law of conservation of energy states that energy can be converted in form, but not created or destroyed.

The unit of measurement for energy in the International System of Units (SI) is the joule (J).

Source: https://en.wikipedia.org/wiki/Energy