diesel
n. uncountablen. a type of heavy oil used as fuel for large engines like trucks, buses, and some cars. It is stronger and thicker than regular gasoline.
n. a heavy petroleum fraction used as fuel in internal combustion engines where ignition is caused by heat from compression rather than a spark.
Most large trucks run on diesel instead of gasoline.
The delivery company switched its entire fleet to diesel to improve fuel efficiency on long-distance routes.
While diesel engines offer superior thermal efficiency compared to petrol counterparts, they have faced increasing regulatory scrutiny due to their higher emissions of nitrogen oxides and particulate matter.
Uncountable when referring to the fuel type; can be used as a modifier before other nouns like 'engine' or 'car'.