fuels
n. C / U B1 Intermediate US //ˈfjuəɫz// UK //fjˈuːəlz// fu·els
n. materials like coal, gas, or wood that people burn to produce heat or power.
n. substances that release energy through combustion or nuclear reaction to provide heat or power.
The car runs on different types of fuels.
Many countries are trying to reduce their reliance on fossil fuels to help the environment.
The transition to sustainable energy requires a significant shift from carbon-heavy fuels to renewable sources like hydrogen or biofuels.
Usage
Uncountable when referring to the substance in general; countable when referring to specific types or varieties of fuel.