1.NounA pair of gears, consisting of a circular pinion that engages with the teeth of a flat bar, that converts rotational into linear motion; used in the steering mechanism of cars, and in some railways.
"This machine transfers a heavy load via a rack and pinion."
2.NounA type of steering that uses such a gear arrangement: Ellipsis of rack and pinion steering.
"This car came with rack and pinion, disc brakes, and a turbocharger at a time when all of those things seemed like exotic luxuries."