Main Entry: valve

Pronunciation: \ˈvalv\

Function: noun

1 : a bodily structure (as the mitral valve) that closes temporarily a passage or orifice or permits movement of fluid in one direction only
2 : any of various mechanical devices by which the flow of liquid (as blood) may be started, stopped, or regulated by a movable part that opens, shuts, or partially obstructs one or more ports or passageways

[valve illustration]

; also : the movable part of such a device