(n) :
(slang) Especially on trucks, an engine compression release braking system that opens the exhaust valves in each cylinder near the top of their compression strokes in order to slow the vehicle; an engine retarder.
(n) :
(slang) Especially on trucks, an engine compression release braking system that opens the exhaust valves in each cylinder near the top of their compression strokes in order to slow the vehicle; an engine retarder.