valve in WordNet English dictionary

1. one of the paired hinged shells of certain molluscs and of brachiopods
   valve 
   
2. the entire one-piece shell of a snail and certain other molluscs
   valve 
   
3. control consisting of a mechanical device for controlling the flow of a fluid
   valve 
   
4. device in a brass wind instrument for varying the length of the air column to alter the pitch of a tone
   valve 
   
5. a structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through it
   valve