energy (n.)

1590s, "force of expression," from French énergie (16c.), from Late Latin energia, from Greek energeia "activity, action, operation," from energos "active, working," from en "at" (see en- (2)) + -ergos "that works," from ergon "work, that which is wrought; business; action" (from PIE root *werg- "to do").

Used by Aristotle with a sense of "actuality, reality, existence" (opposed to "potential") but this was misunderstood in Late Latin and afterward as "force of expression," as the power which calls up realistic mental pictures. Broader meaning of "power" in English is first recorded 1660s. Scientific use is from 1807. Energy crisis first attested 1970.

updated on September 19, 2021

Definitions of energy from WordNet
energy (n.)
(physics) a thermodynamic quantity equivalent to the capacity of a physical system to do work; the units of energy are joules or ergs;
energy can take a wide variety of forms
Synonyms: free energy
energy (n.)
forceful exertion;
he plays tennis with great energy
Synonyms: vigor / vigour / zip
energy (n.)
enterprising or ambitious drive;
Europeans often laugh at American energy
Synonyms: push / get-up-and-go
energy (n.)
an imaginative lively style (especially style of writing);
his writing conveys great energy
Synonyms: muscularity / vigor / vigour / vim
energy (n.)
a healthy capacity for vigorous activity;
jogging works off my excess energy
Synonyms: vim / vitality
energy (n.)
any source of usable power;
the DOE is responsible for maintaining the energy policy
Energy (n.)
the federal department responsible for maintaining a national energy policy of the United States; created in 1977;
Synonyms: Department of Energy / Energy Department / doe
Etymologies are not definitions. From, not affiliated with etymonline.