<p><strong>Noun</strong></p><ul><li>The capacity for vigorous activity; available power: I eat chocolate to get quick energy.</li><li>Synonyms: potency, force, vigor.</li><li>An adequate or abundant amount of such power: I seem to have no energy these days.</li><li>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.</li><li>An exertion of such power: She plays tennis with great energy.</li><li>The habit of vigorous activity; vigor as a characteristic: Foreigners both admire and laugh at American energy.</li><li>Synonyms: push, zeal.</li><li>The ability to act, lead others, effect, etc., forcefully.</li><li>Forcefulness of expression: a writing style abounding with energy.</li><li>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.</li><li>Any source of usable power, as fossil fuel, electricity, or solar radiation.</li></ul>