noun en·er·gy \ˈe-nər-jē\

Definition of energy



  1. 1 a :  dynamic quality <narrative energy> b :  the capacity of acting or being active <intellectual energy> c :  a usually positive spiritual force <the energy flowing through all people>

  2. 2 :  vigorous exertion of power :  effort <investing time and energy>

  3. 3 :  a fundamental entity of nature that is transferred between parts of a system in the production of physical change within the system and usually regarded as the capacity for doing work

  4. 4 :  usable power (as heat or electricity); also :  the resources for producing such power

Examples of energy in a sentence

  1. The kids are always so full of energy.

  2. They devoted all their energy to the completion of the project.

  3. They devoted all their energies to the completion of the project.

  4. She puts a lot of energy into her work.

  5. The newer appliances conserve more energy.

Origin and Etymology of energy

Late Latin energia, from Greek energeia activity, from energos active, from en in + ergon work — more at work

First Known Use: 1599

Synonym Discussion of energy

power, authority, jurisdiction, control, command, sway, dominion mean the right to govern or rule or determine. power implies possession of ability to wield force, authority, or influence <the power to mold public opinion>. authority implies power for a specific purpose within specified limits <granted the authority to manage her estate>. jurisdiction applies to official power exercised within prescribed limits <the bureau having jurisdiction over parks>. control stresses the power to direct and restrain <you are responsible for the students under your control>. command implies the power to make arbitrary decisions and compel obedience <the army officer in command>. sway suggests the extent of exercised power or influence <the empire extended its sway over the region>. dominion stresses sovereign power or supreme authority <given dominion over all the animals>.

power, force, energy, strength, might mean the ability to exert effort. power may imply latent or exerted physical, mental, or spiritual ability to act or be acted upon <the awesome power of flowing water>. force implies the actual effective exercise of power <used enough force to push the door open>. energy applies to power expended or capable of being transformed into work <a worker with boundless energy>. strength applies to the quality or property of a person or thing that makes possible the exertion of force or the withstanding of strain, pressure, or attack <use weight training to build your strength>. might implies great or overwhelming power or strength <the belief that might makes right>.

ENERGY Defined for English Language Learners


noun en·er·gy \ˈe-nər-jē\

Definition of energy for English Language Learners

  • : ability to be active : the physical or mental strength that allows you to do things

  • : natural enthusiasm and effort

  • : usable power that comes from heat, electricity, etc.

ENERGY Defined for Kids


noun en·er·gy \ˈe-nər-jē\

Definition of energy for Students



  1. 1 :  ability to be active :  strength of body or mind to do things or to work <The children … were tired and hardly had energy enough to walk. — E. B. White, Charlotte's Web>

  2. 2 :  strong action or effort <He puts a lot of energy into his work.>

  3. 3 :  usable power or the resources (as oil) used to produce usable power <Our new dryer uses a lot less energy.>

Medical Dictionary


noun en·er·gy \ˈen-ər-jē\

Medical Definition of energy



  1. 1:  psychic energy

  2. 2:  the capacity for doing work

Seen and Heard

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a harsh rebuke

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