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” ( see focus) + -ālis -al ¹

Explanation

What do you and your car have in common? You both run on fuel. Whether its gasoline or nutritious food, fuel produces energy to get up and go. Fuel can also act as a verb that has several different meanings, all related to stimulating something or providing energy. Your brother might fuel up on whole-wheat bread with peanut butter a few hours before a big game. A teacher assigns readings to fuel meaningful class discussion. Memories of your mom's delicious dinners might fuel your desire to learn to cook.

Example Sentences

Fuel is generally among the biggest expenses for airlines and cruise-ship companies.

From MarketWatch • May 27, 2026

Other notable cars on display include Bill Vukovich’s 1953 and ’54 winning car, the No. 14 Fuel Injection Special Kurtis-Kraft, and Johnny Rutherford’s 1980 Pennzoil Chaparral 2K.

From The Wall Street Journal • May 20, 2026

Fuel thefts have surged by 62% across the UK compared to a year ago, according to BBC figures - with one forecourt owner saying drive-offs are costing him £2,000 a week across his five sites.

From BBC • May 16, 2026

A company called Global Nuclear Fuel Americas, which is jointly owned by GE Vernova and Hitachi, also won a grant worth $3 million to make fuel rods in North Carolina.

From Barron's • May 14, 2026

Fuel being scarce, and the Staniford Street house being draughty, I offered my services to a work crew in exchange for wood.

From "The Astonishing Life of Octavian Nothing, Traitor to the Nation, Volume II: The Kingdom on the Waves" by M.T. Anderson

Related Words

• ammunition
• electricity
• food
• gas
• material