an engine of one or more working cylinders in which the process of combustion takes place within the cylinders.
Origin of internal-combustion engine
First recorded in 1880–85
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a heat engine in which heat is supplied by burning the fuel in the working fluid (usually air)
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
An engine whose fuel is burned inside the engine itself rather than in an outside furnace or burner. Gasoline and diesel engines are internal-combustion engines, as are gas turbine engines such as turbojets. Compare steam engine.
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