The word “energy” has the Greek origin “Enérgeia”. Developed by Aristotle, Enérgeia has no direct translation to English, although it is frequently described as “being at work”.
Energy was first used in the English language in the 1660s, referring to power.
Aristotle (384 BC – 322 BC)
Although the term “energy” first emerged in its current capacity in the 19th century, the ideas behind the concept started forming at the end of the 17th century.
By 1686, Gottfried Wilhelm von Leibniz, had already developed concepts that correspond to our current understanding of kinetic and potential mechanical energy.
However, he didn’t use the term “energy”.
Gottfried Wilhelm von Leibniz (1646 – 1716)
The word “energy” was first introduced to physics in 1800 by Thomas Young, but the term did not gain popularity.
Thomas Young later established the wave nature of light through interference experiments.
Thomas Young (1773 – 1829)
The term “work” was defined in 1828/29 by Gustave Gaspard de Coriolis and Jean Victor Poncelet.
In the years 1842-1847, Julius Robert von Mayer, James Prescott Joule, and Hermann Ludwig Ferdinand von Helmholtz discovered and formulated the following statement that we refer to today as the law of conservation of energy:
Energy cannot be created or destroyed; it can only be transformed from one form to another.
Instead of the word “energy”, they used the terms “living force” and “tensional force” or “fall-force”.
In 1851-1852, William Thomson (Lord Kelvin) and William J. M. Rankine introduced the term “energy” to replace related terms using the word “force” in all branches of science.
Finally, in 1905 Albert Einstein established the general equivalence between energy and mass with the theory of relativity. From there, the concept of “energy” was generalized into the form used today.
Everyday expressions such as “energy production” or “renewable energy” contradict the energy conservation law, which says that energy cannot be created or destroyed. The scientific definition of energy by the law of energy conservation also doesn’t help us understand expressions like “an energetic person”.
However, this phrase provides some direction for an everyday definition of energy, which harkens back to that of Aristotle:
Energy is a condition that describes the capacity to do work.