diaphragm
noun
°In mammals, a sheet of muscle separating the thorax from the abdomen, contracted and relaxed in respiration to draw air into and expel air from the lungs; also called thoracic diaphragm.
°Any of various membranes or sheets of muscle or ligament which separate one cavity from another.
verb
°To reduce lens aperture using an optical diaphragm.
°To act as a diaphragm, for example by vibrating.