Definition of energy in English:


Line breaks: en¦ergy
Pronunciation: /ˈɛnədʒi

noun (plural energies)

[mass noun]
1The strength and vitality required for sustained physical or mental activity: changes in the levels of vitamins can affect energy and well-being
More example sentences
  • The mental activity consumes energy and can, in the event of excess, lead to overstrain.
  • The main modifiable factors affecting energy balance are dietary energy intake and energy expended through physical activity.
  • When people are under stress, they don't have as much energy for physical or mental activity.
1.1 (energies) A person’s physical and mental powers: an alternative is to devote your energies to voluntary work
More example sentences
  • There is a need to focus mental energies and prepare yourself to face competition.
  • You are a physical person, but you know how to control and use of your physical energies.
  • I was amazed at the creative energies expended in getting people to give and increase their pledges.
2Power derived from the utilization of physical or chemical resources, especially to provide light and heat or to work machines: nuclear energy
More example sentences
  • These include global warming, energy efficiency and renewable energy resources.
  • It will also provide virtually unlimited energy and material resources for humankind.
  • That efficiency will include solar power, recyclable energy and heat retention.
3 Physics The property of matter and radiation which is manifest as a capacity to perform work (such as causing motion or the interaction of molecules): a collision in which no energy is transferred
More example sentences
  • Why is that electrons radiate electromagnetic energy when they are accelerated?
  • If a particle moves faster than the speed of light, it must create a shockwave, and radiate energy.
  • The protons are set in motion and, being charged, they again deposit energy through electrical interactions.


mid 16th century (denoting force or vigour of expression): from French énergie, or via late Latin from Greek energeia, from en- 'in, within' + ergon 'work'.

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