Pronunciation: (en'ur-jē),[key] —n., —pl.-gies. 1. the capacity for vigorous activity; available power: I eat chocolate to get quick energy. 2. an adequate or abundant amount of such power: I seem to have no energy these days. 3. Often, energies. a feeling of tension caused or seeming to be caused by an excess of such power: to work off one's energies at tennis. 4. an exertion of such power: She plays tennis with great energy. 5. the habit of vigorous activity; vigor as a characteristic: Foreigners both admire and laugh at American energy. 6. the ability to act, lead others, effect, etc., forcefully.
7. forcefulness of expression: a writing style abounding with energy. 8. Physics.the capacity to do work; the property of a system that diminishes when the system does work on any other system, by an amount equal to the work so done; potential energy. Symbol: E
9. any source of usable power, as fossil fuel, electricity, or solar radiation.