Our universe is made up of 2 things that is matter and energy. It is pretty easy to understand the concept of matter because anything which occupy space and has a mass can be defined as matter. When you try to understand energy, it is much more complex. If you go according to the technical definition of energy, energy can be defined as the ability to move things or to do any kind of work. You can exclaim that energy is the ability of anything to do a certain type of work.