diaphragm

1. 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. · thoracic diaphragm· pulmonary diaphragm
2. Any of various membranes or sheets of muscle or ligament which separate one cavity from another.
3. A contraceptive device consisting of a flexible cup, used to cover the cervix during intercourse. · cervical diaphragm· contraceptive diaphragm
4. A flexible membrane separating two chambers and fixed around its periphery that distends into one or other chamber as the difference in the pressure in the chambers varies.
5. In a speaker, the thin, semi-rigid membrane which vibrates to produce sound. · acoustic diaphragm
6. A thin opaque structure with a central aperture, used to limit the passage of light into a camera or similar device.
7. A permeable or semipermeable membrane.
8. A floor slab, metal wall panel, roof panel or the like, having a sufficiently large in-plane shear stiffness and sufficient strength to transmit horizontal forces to resisting systems.

Plural diaphragms