energy

American  

[en-er-jee] / ˈɛn ər dʒi /

noun

energies plural

1. the capacity for vigorous activity; available power.

   I eat chocolate to get quick energy.

   Synonyms:

   potency, force, vigor

2. an adequate or abundant amount of such power.

   I seem to have no energy these days.

3. Often energies. a feeling of tension caused or seeming to be caused by an excess of such power.

   to work off one's energies at tennis.

4. an exertion of such power.

   She plays tennis with great energy.

5. the habit of vigorous activity; vigor as a characteristic.

   Foreigners both admire and laugh at American energy.

   Synonyms:

   push, zeal

6. the ability to act, lead others, effect, etc., forcefully.

7. forcefulness of expression.

   a writing style abounding with energy.

8. Physics. the capacity to do work; the property of a system that diminishes when the system does work on any other system, by an amount equal to the work so done; potential energy. E

9. any source of usable power, as fossil fuel, electricity, or solar radiation.

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energy British  

/ ˈɛnədʒɪ /

noun

1. intensity or vitality of action or expression; forcefulness

2. capacity or tendency for intense activity; vigour

3. vigorous or intense action; exertion

4. physics

   1. the capacity of a body or system to do work

   2.  E.  a measure of this capacity, expressed as the work that it does in changing to some specified reference state. It is measured in joules (SI units)

5. a source of power See also kinetic energy potential energy

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energy Scientific  

/ ĕn′ər-jē /

1. The capacity or power to do work, such as the capacity to move an object (of a given mass) by the application of force. Energy can exist in a variety of forms, such as electrical, mechanical, chemical, thermal, or nuclear, and can be transformed from one form to another. It is measured by the amount of work done, usually in joules or watts.

2. See also conservation of energy kinetic energy potential energy Compare power work

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Usage

What is energy? Energy refers to available power or motivation to move, as in Jada found that getting enough sleep each night gave her the energy to live each day. Energy also refers to power that is used with exertion or force, as in Monique brought energy to the team, leading them to win more games. In physics, energy is the power or heat that is created when something moves, is burned, or is exerted. It is typically represented in two forms: potential and kinetic energy. Potential energy is power that is stored in something as it sits still or is unburned. For example, coal contains a large amount of potential energy that is released when the coal is burned. As the coal burns, that potential energy becomes kinetic energy, energy related to the particles in the system. Energy is a common word with several other senses related to power or motivation. Example: Darryl found out the hard way that cell phone batteries lose their energy in the cold.

Other Word Forms

Derived Forms

• hyperenergy
  noun
• self-energy
  noun

Inflected Forms

Nouns

• energies
  plural

Etymology

Origin of energy

First recorded in 1575–85; from Late Latin energīa, from Greek enérgeia “activity,” equivalent to energe- (stem of energeîn “to be active”; see en- ², work) + -ia -y ³

Explanation

The general meaning of energy is the ability to be active. If you have a lot of energy, it means you like to be active. If you plan a low-energy day, it means a day of lounging around. Energy is from Greek energeia "activity, operation," from energos "active, effective," from en "in" plus ergon "work." Specialized senses of the word energy include the power that comes from sources such as heat or electricity, and the ability of sources such as heat or light to do work. In physics, an erg is the centimeter-gram-second unit used to measure the amount of energy or the amount of work done.

Example Sentences

See Examples For:

energy energies

He added that it promises to “create thousands of jobs, lower electricity costs for American families, and deliver energy infrastructure needed to power the AI economy.”

From MarketWatch ● Jul. 27, 2026

“Each item I collect has a certain energy from its previous function that carries over into its new use.”

From Los Angeles Times ● Jul. 27, 2026

In 2011, a solar energy manufacturer named Solyndra declared bankruptcy.

From Slate ● Jul. 27, 2026

The energy shock once again captured the attention of bond and equity markets.

From The Wall Street Journal ● Jul. 27, 2026

A little extra sleep then would give him more energy for his midnight flights with Tiamat.

From "Jeremy Thatcher, Dragon Hatcher" by Bruce Coville

At low energies and under conditions of weak spacetime curvature, the equations of Gravity from Entropy reproduce General Relativity.

From Science Daily ● Jul. 21, 2026

“It would have been interesting to see what the bipartisan America250 initiative could have come up with if its funding and energies had not been diverted.”

From Los Angeles Times ● Jul. 3, 2026

In the tunnel, running about 100 metres below the French-Swiss border area, superconducting magnets and accelerating structures propel particles to extreme energies and then smash them together at phenomenal speeds.

From Barron's ● Jun. 27, 2026

But they did understand something far more enduring: that the fortunes of a nation are shaped by the energies of its people.

From The Wall Street Journal ● Jun. 23, 2026

May these, as we go to still higher energies, in turn be found to be made from still smaller particles?

From "A Brief History of Time: And Other Essays" by Stephen Hawking

Related Words

• efficiency
• intensity
• power
• spirit
• stamina
• strength
• toughness
• vitality