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Synonyms

diesel

1 American  
[dee-zuhl, -suhl] / ˈdi zəl, -səl /
Or Diesel

adjective

  1. noting a machine or vehicle powered by a diesel engine.

    diesel locomotive.

  2. of or relating to a diesel engine.

    diesel fuel.

noun

  1. diesel engine.

  2. a vehicle powered by a diesel engine.

  3. diesel fuel.

Diesel 2 American  
[dee-zuhl, -suhl] / ˈdi zəl, -səl /

noun

  1. Rudolf 1858–1913, German automotive engineer.

diesel 1 British  
/ ˈdiːzəl /

noun

  1. See diesel engine

  2. a ship, locomotive, lorry, etc, driven by a diesel engine

  3. informal short for diesel oil

  4. slang any cola drink

    spook and diesel

  5. See suck

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Diesel 2 British  
/ ˈdiːzəl /

noun

  1. Rudolf (ˈruːdɔlf). 1858–1913, German engineer, who invented the diesel engine (1892)

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of diesel

After R. Diesel, the engine's inventor

Explanation

A diesel is a type of engine that produces enough heat to burn fuel and power a vehicle. Most diesels run on very thick, heavy oil. Large trucks use diesels — also known as diesel engines — and so do some cars, trains, and ships. The earliest diesel was developed in the late 19th century, and its invention is credited to the German engineer Rudolph Diesel, although other inventors laid the groundwork with their development of a very similar type of engine.

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The crisis has raised average gasoline prices to $4.15 a gallon and diesel to $5.68 a gallon, although there are signs that those may have peaked — for now.

From MarketWatch • Apr. 10, 2026

Across California, the epicenter of the fallout, average diesel prices on Thursday reached $7.75 a gallon.

From The Wall Street Journal • Apr. 9, 2026

It comes from the surrounding landscape, including farm fields, livestock operations, diesel exhaust and unpaved roads.

From Los Angeles Times • Apr. 9, 2026

Red diesel, a fuel used by farmers in off-road vehicles, machinery and heating has seen its price pushed up by the soaring cost of brent crude - the global benchmark for oil prices.

From BBC • Apr. 8, 2026

The dingy bellow of a truck’s diesel exhaust.

From "I Can Make This Promise" by Christine Day

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.