D defs.my
Entry 2 senses Webster, 1913

Air chamber

/ĕr chām'-bẽr/ · Air· cham·ber · IPA
01 A chamber or cavity filled with air, in an animal or plant.
  1. 1.
    A chamber or cavity filled with air, in an animal or plant.
  2. 2.
    A cavity containing air to act as a spring for equalizing the flow of a liquid in a pump or other hydraulic machine.