fuel

American  

[fyoo-uhl] / ˈfyu əl /

noun

1. combustible matter used to maintain fire, as coal, wood, oil, or gas, in order to create heat or power.

2. something that gives nourishment; food.

3. an energy source for engines, power plants, or reactors.

   Kerosene is used as jet engine fuel.

4. something that sustains or encourages; stimulant.

   Our discussion provided him with fuel for debate.

   Synonyms:

   stimulus, impetus, sustenance, ammunition

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verb (used with object)

fueled, fueling, fuelled, fuelling

1. to supply with fuel.

verb (used without object)

fueled, fueling, fuelled, fuelling

1. to obtain or replenish fuel.

fuel British  

/ fjʊəl /

noun

1. any substance burned as a source of heat or power, such as coal or petrol

2. 1. the material, containing a fissile substance, such as uranium-235, that produces energy in a nuclear reactor

   2. a substance that releases energy in a fusion reactor

3. something that nourishes or builds up emotion, action, etc

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verb

1. to supply with or receive fuel

fuel Scientific  

/ fyo̅o̅′əl /

1. A substance that produces useful energy when it undergoes a chemical or nuclear reaction. Fuel such as coal, wood, oil, or gas provides energy when burned. Compounds in the body such as glucose are broken down into simpler compounds to provide energy for metabolic processes. Some radioactive substances, such as plutonium and tritium, provide energy by undergoing nuclear fission or fusion.

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fuel Idioms  

1. see add fuel to the fire.

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Other Word Forms

• defuel verb (used with object)
• fueler noun
• fueller noun
• nonfuel adjective
• unfueled adjective
• well-fueled adjective

Etymology

Origin of fuel

First recorded in 1300–50; Middle English feuel, fuel(le), from Old French feuaile, from Vulgar Latin focālia (unrecorded), neuter plural of focālis (unrecorded) “of the hearth, fuel,” from Latin focus “hearth” ( focus ) + -ālis -al ¹

Example Sentences

Life in the apartments revolves around work—and the fuel required to keep going.

From The Wall Street Journal • Apr. 4, 2026

For Ukraine, the potential scarcity of fuel and surge in prices caused by the war on Iran is a worry: its own frontline troops need large amounts of diesel for their tanks and vehicles.

From BBC • Apr. 3, 2026

Flores is an example of how sky-rocketing fuel prices are having ripple effects throughout the economy.

From Los Angeles Times • Apr. 3, 2026

It should boost revenue, although investors have a more immediate reason to relax Wednesday—falling fuel prices.

From Barron's • Apr. 3, 2026

The poison tide had killed off the coastal vegetation, making it the perfect fuel for a wildfire.

From "The Wild Robot Protects" by Peter Brown

Related Words

• ammunition
• electricity
• food
• gas
• material