Energy is a general concept of strength, force, or ability to create an effect and can be either physical or mental.
The word energy is borrowed and comes from multiple languages. It is partly a borrowing from Greek and partly from Latin. While the word was borrowed around 1545, the modern definitions of it was not around until 1784 and after. The prior definitions were very similar though. When it was first borrowed in the 1500s, the spellings began as enargie, energye, and energy. This is fairly similar to the Latin energia and Greek ἐνέργεια, as well as the Middle French energie. The change from -ie- to -y is important to note as it is similar to other word spelling changes over time.
Energy is important to learn about as all things in the universe use energy. This is a catch all term for the ability to do something. This could be the energy used to power a lightbulb, energy to deal with a screaming child, or the energy in a room. This can also be used to describe otherworldly entities as they also possess the capability to create an effect. There are several types of energy, typically labeled as "Potential," or stored, energy and "Kinetic," or working, energy.
Sources:
“Energy, N.” Oxford English Dictionary, Oxford UP, June 2024, https://doi.org/10.1093/OED/9992006561.
“U.S. Energy Information Administration - EIA - Independent Statistics and Analysis.” What Is Energy? Explained - U.S. Energy Information Administration (EIA), www.eia.gov/energyexplained/what-is-energy/. Accessed 6 Aug. 2024.