Baffle

[1] An obstruction (e.g., plate or vane) used to slow down or divert the flow of gases, liquids, sound, etc. They are found in the fuel tank, crankcase, muffler, and radiator.
[2] Extended surface surrounding a diaphragm of a sound source (loudspeaker) so that an acoustic short-circuit is prevented.
[3] Any device to impede or divide a fluid flow in a tank to reduce sloshing of liquid.
[3] Plates fitted between cylinders of air-cooled engines to assist cooling.
[4] Internal structure or electrode, with no external connection, used in gas-filled tubes to control the discharge or its decay.
See also arc baffle, box baffle,