a valve that regulates the supply of fuel to the engine | one of the paired hinged shells of certain molluscs and of brachiopods |
a scientific instrument that increases the kinetic energy of charged particles | the entire one-piece shell of a snail and certain other molluscs |
a pedal that controls the throttle valve | control consisting of a mechanical device for controlling the flow of a fluid |
(chemistry) a substance that initiates or accelerates a chemical reaction without itself being affected | device in a brass wind instrument for varying the length of the air column to alter the pitch of a tone |
| a structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through it |