Noun

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; also called thoracic 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.
4. A flexible membrane separating two chambers and fixed around its periphery that distends into one or other chamber depending on the as the difference in the pressure in the chambers varies.
5. In a speaker, the thin, semi-rigid membrane which vibrates to produce sound.
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
   • 1. A floor slab, metal wall panel, roof panel or the like, havig a sufficiently large in-plane shear stiffness and sufficient strength to transmit horizontal forces to resisting systems.
     
     

     Verb

     
     
     
     1. To reduce lens aperture using an optical diaphragm.
        • 1. To act as a diaphragm, for example by vibrating.