noun en·er·gy \ ˈe-nər-jē \
Updated on: 19 Apr 2018

Definition of energy

plural energies
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 : vigorous exertion of power : effort
  • investing time and energy
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 : usable power (such 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.

Recent Examples of energy from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'energy.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of energy

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

Synonym Discussion of energy

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


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

plural energies
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 : strong action or effort
  • He puts a lot of energy into his work.
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

plural energies
2 : the capacity for doing work

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without deliberation, pause, or delay

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