opposed-piston engine

[ uh-pohzd-pis-tuh n ]
/ əˈpoʊzdˈpɪs tən /

noun

a reciprocating engine, as a diesel engine, in which each cylinder has two pistons that move simultaneously away from or toward the center.

Origin of opposed-piston engine

First recorded in 1965–70
Also called opposed engine.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019