Meaning : A structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through it.

Meaning : Device in a brass wind instrument for varying the length of the air column to alter the pitch of a tone.

Meaning : Control consisting of a mechanical device for controlling the flow of a fluid.

Meaning : The entire one-piece shell of a snail and certain other molluscs.

Meaning : One of the paired hinged shells of certain molluscs and of brachiopods.