1. ability to do things: the ability or power to work or make an effort His illness left him feeling drained of energy.
2. vigor: liveliness and forcefulness She gave a performance that was full of energy.
3. forceful effort: a vigorous effort or action We must concentrate our energies on the task in hand.
4. power supply or source: a supply or source of electrical, mechanical, or other form of power
5. physics capacity to do work: the capacity of a body or system to do work. Symbol E
[Mid-16th century. Via French< Greek energeia< ergon "work." < Indo-European]
Word History
The Indo-European word from which energy is ultimately derived is also the ancestor of English liturgy, organ, orgy, surgery, and work, and perhaps also of irk.
