Webster 1913 Edition



, LL.
, fr. Gr.[GREEK], fr. [GREEK] active; [GREEK] in + [GREEK] work. See
, and
Internal or inherent power; capacity of acting, operating, or producing an effect, whether exerted or not;
as, men possessing
may suffer them to lie inactive
The great
of nature are known to us only by their effects.
Power efficiently and forcibly exerted; vigorous or effectual operation;
as, the
of a magistrate
Strength of expression; force of utterance; power to impress the mind and arouse the feelings; life; spirit; – said of speech, language, words, style;
as, a style full of
Capacity for performing work.
☞ The kinetic energy of a body is the energy it has in virtue of being in motion. It is measured by one half of the product of the mass of each element of the body multiplied by the square of the velocity of the element, relative to some given body or point. The available kinetic energy of a material system unconnected with any other system is that energy which is due to the motions of the parts of the system relative to its center of mass. The potential energy of a body or system is that energy which is not kinetic; – energy due to configuration. Kinetic energy is sometimes called actual energy. Kinetic energy is exemplified in the vis viva of moving bodies, in heat, electric currents, etc.; potential energy, in a bent spring, or a body suspended a given distance above the earth and acted on by gravity.
Syn. – Force; power; potency; vigor; strength; spirit; efficiency; resolution.

Webster 1828 Edition



[Gr. work.]
Internal or inherent power; the power of operating, whether exerted or not; as men possessing energies sometimes suffer them to lie inactive. Danger will rouse the dormant energies of our natures into action.
Power exerted; vigorous operation; force; vigor. God, by his Almighty energy, called the universe into existence. The administration of the laws requires energy in the magistrate.
Effectual operation; efficacy; strength or force producing the effect.
Beg the blessed Jesus to give an energy to your imperfect prayers, by his most powerful intercession.
Strength of expression; force of utterance; life; spirit; emphasis. The language of Lord Chatham is remarkable for its energy.

Definition 2023





energy (countable and uncountable, plural energies)

  1. The impetus behind all motion and all activity.
    • 2013 June 1, Ideas coming down the track”, in The Economist, volume 407, number 8838, page 13 (Technology Quarterly):
      A “moving platform” scheme [] is more technologically ambitious than maglev trains even though it relies on conventional rails. [] This set-up solves several problems []. Stopping high-speed trains wastes energy and time, so why not simply slow them down enough for a moving platform to pull alongside?
  2. The capacity to do work.
    • 1915, George A. Birmingham, chapter I”, in Gossamer (Project Gutenberg; EBook #24394), London: Methuen & Co., published 8 January 2013 (Project Gutenberg version), OCLC 558189256:
      There is an hour or two, after the passengers have embarked, which is disquieting and fussy. [] Stewards, carrying cabin trunks, swarm in the corridors. Passengers wander restlessly about or hurry, with futile energy, from place to place.
  3. (physics) A quantity that denotes the ability to do work and is measured in a unit dimensioned in mass × distance²/time² (ML²/T²) or the equivalent.
    SI: joule (J), kilowatt-hour (kW·h)
    CGS: erg (erg)
    Customary: foot-pound-force, calorie, kilocalorie (i.e. dietary calories), BTU, liter-atmosphere, ton of TNT
  4. (New Age jargon) An intangible, modifiable force (often characterized as either 'positive' or 'negative') believed to emanate from a person, place or thing and which is (or can be) preserved and transferred in human interactions; shared mood or group habit; a vibe, a feeling, an impression.
    • 2004, Phylameana L. Desy, The Everything Reiki Book, Body, Mind & Spirit, p.130
      Reiki, much like prayer, is a personal exercise that can easily convert negative energy into positive energy.
    • 2009, Christopher Johns, Becoming a Reflective Practitioner, John Wiley & Sons, p.15
      Negative feelings can be worked through and their energy converted into positive energy []. In crisis, normal patterns of self-organization fail, resulting in anxiety (negative energy). Being open systems, people can exchange this energy with the environment and create positive energy for taking action based on a reorganisation of self as necessary to resolve the crisis and emerge at a higher level of consciousness; that is, until the next crisis.
    • 2011, Anne Jones, Healing Negative Energies, Hachette, p.118
      If you have been badly affected by negative energy a salt bath is wonderful for clearing and cleansing yourself []. Salt attracts negative energy and will draw it away from you.
  5. (role-playing games, video games, board games) A measure of how many actions a player or unit can take; in the fantasy genre often called magic points or mana.



Derived terms

Related terms



External links

  • energy in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913
  • energy in The Century Dictionary, The Century Co., New York, 1911



  1. Containing energy
    Energy drink
    Energy Signal