energy

American  

[en-er-jee] / ˈɛn ər dʒi /

noun

plural

energies

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

• hyperenergy noun
• self-energy noun

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”; 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

The table below shows the eight energy facilities with the highest levels of damage.

From MarketWatch • Apr. 11, 2026

The nationwide controversy surrounding high-tech data centers, and impact and energy and water supplies, turned into a police matter not far from the U.S.-Mexico border.

From Los Angeles Times • Apr. 11, 2026

Barron’s Lauren Rublin and Avi Salzman speak with Denton Cinquegrana, chief oil analyst at OPIS, about the latest outlook for oil, gas, and energy stocks.

From Barron's • Apr. 11, 2026

A spokesperson for Blackford Energy Park said battery energy storage systems "contribute to energy security, and, importantly, help to create a more efficient, resilient, and affordable energy system."

From BBC • Apr. 11, 2026

It’s one of her favorite games and I don’t have the energy today.

From "South of Somewhere" by Kalena Miller

Related Words

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