How do we define Matter + Energy?

“Matter + Energy form the basis for life. “Living organisms <which are comprised of matter> require available energy to stay alive, such as the energy humans get from food. Civilisation gets the energy it needs from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The processes of Earth’s climate and ecosystem are driven by the radiant energy Earth receives from the sun and the geothermal energy contained within the earth. Wikipedia

Mass and energy are closely related. According to the theory of mass–energy equivalence, any object that has mass when stationary … also has an equivalent amount of energy …” Wikipedia

Matter is the “stuff” of the universe — the atoms, molecules and ions that make up all physical substances. Matter is anything that has mass and takes up space. Energy is the capacity to cause change. Energy cannot be created or destroyed; it can only be conserved and converted from one form to another.” Live Science