Pronunciation: (fôr'sī"kul, fōr'-), [key]
noting or pertaining to an internal-combustion engine in which a complete cycle in each cylinder requires four strokes, one to draw in air or an air-fuel mixture, one to compress it, one to ignite it and do work, and one to scavenge the cylinder. Also,four-stroke.Cf. two-cycle.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.