Definition of valves:
(n) :
A device that controls the flow of a gas or fluid through a space, such as a pipe, manifold, or plenum.
(n) :
Such a device that admits fuel and air into the cylinder of an internal combustion engine, or one that allows combustion gases to exit.
(n) :
(anatomy) One or more membranous partitions, flaps, or folds, which permit the passage of the contents of a vessel or cavity in one direction, but stop or control the flow in the opposite direction.
(n) :
(chiefly British) A vacuum tube.
(n) :
One of the leaves of a folding door or of a window sash.
(v) :
(transitive) To control (flow) by means of a valve.