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

---

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

---

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.

---

fuel Idioms  

1. see add fuel to the fire.

---

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

Ireland has cut taxes on petrol and diesel, Australia has halved fuel duty for three months and Slovenia has become the first EU member state to introduce fuel rationing.

From BBC • Apr. 3, 2026

Some economists expect the war in Iran—which has rattled energy markets, driven up fuel costs and dragged the U.S. stock market to its worst quarter in nearly four years—to damp growth in the short term.

From The Wall Street Journal • 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

Jet fuel prices have surged around 70% since the start of the fighting.

From Barron's • Apr. 3, 2026

While units 4, 5, and 6 were shut down before the earthquake and tsunami, those three reactors still held spent fuel in storage pools, and even spent fuel needs to be kept cool.

From "Meltdown" by Deirdre Langeland

Related Words

• ammunition
• electricity
• food
• gas
• material