'Exhaust valve' definitions:

Definition of 'exhaust valve'

noun

A valve through which burned gases from a cylinder escape into the exhaust manifold

From: GCIDE

Exhaust \Ex*haust"\, a. [L. exhaustus, p. p.]
1. Drained; exhausted; having expended or lost its energy. [1913 Webster]
2. Pertaining to steam, air, gas, etc., that is released from the cylinder of an engine after having preformed its work. [1913 Webster]
Exhaust draught, a forced draught produced by drawing air through a place, as through a furnace, instead of blowing it through.
Exhaust fan, a fan blower so arranged as to produce an exhaust draught, or to draw air or gas out of a place, as out of a room in ventilating it.
Exhaust nozzle, Exhaust orifice (Steam Engine), the blast orifice or nozzle.
Exhaust pipe (Steam Engine), the pipe that conveys exhaust steam from the cylinder to the atmosphere or to the condenser.
Exhaust port (Steam Engine), the opening, in the cylinder or valve, by which the exhaust steam escapes.
Exhaust purifier (Milling), a machine for sorting grains, or purifying middlings by an exhaust draught. --Knight.
Exhaust steam (Steam Engine), steam which is allowed to escape from the cylinder after having been employed to produce motion of the piston.
Exhaust valve (Steam Engine), a valve that lets exhaust steam escape out of a cylinder. [1913 Webster]