Energy (noun)

1. The ability to do work or cause change.
2. A natural force, such as electricity or heat, that can be transferred and transformed but is not destroyed.

Origin:

From the latin word "energia" meaning "activity" or "operation", which comes from the greek "energeia" meaning "working" or "operation". it first appeared in english in the early 17th century.

Examples:

1. Solar energy is a clean and renewable source of power.
2. He had a lot of energy and was always on the go.
3. The company is investing in new forms of energy.
4. The experiment was able to convert heat energy into electrical energy.
5. The car runs on a hybrid energy system.