plural diesels
1
: a vehicle (such as a truck or bus) that has a diesel engine
His truck's a diesel.
2
: diesel fuel
Does your car take diesel or gasoline?
Cite this Entry
“Diesel.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/diesel. Accessed 21 Jun. 2026.
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