noun \ˈe-nər-jē\

: 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.

plural en·er·gies

Full Definition of ENERGY

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>
:  vigorous exertion of power :  effort <investing time and energy>
:  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
:  usable power (as heat or electricity); also :  the resources for producing such power

Examples of ENERGY

  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 of ENERGY

Late Latin energia, from Greek energeia activity, from energos active, from en in + ergon work — more at work
First Known Use: 1599

Other Physics Terms

amplitude, centrifugal, centripetal, convection, gradient, hysteresis, kinetic, lase, quantum


noun \ˈen-ər-jē\   (Medical Dictionary)
plural en·er·gies

Medical Definition of ENERGY

: the force driving and sustaining mental activity <in psychoanalytic theory the source of psychic energy is the id>
: the capacity for doing work


noun    (Concise Encyclopedia)

Capacity for doing work. Energy exists in various forms—including kinetic, potential, thermal, chemical, electrical (see electricity), and nuclear—and can be converted from one form to another. For example, fuel-burning heat engines convert chemical energy to thermal energy; batteries convert chemical energy to electrical energy. Though energy may be converted from one form to another, it may not be created or destroyed; that is, total energy in a closed system remains constant. All forms of energy are associated with motion. A rolling ball has kinetic energy, for instance, whereas a ball lifted above the ground has potential energy, as it has the potential to move if released. Heat and work involve the transfer of energy; heat transferred may become thermal energy. See also activation energy, binding energy, ionization energy, mechanical energy, solar energy, zero-point energy.


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