Definition from Wiktionary, the free dictionary
diaphragm (plural diaphragms)
- (anatomy) 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.
- (anatomy) Any of various membranes or sheets of muscle or ligament which separate one cavity from another.
- A contraceptive device consisting of a flexible cup, used to cover the cervix during intercourse.
- (mechanics) 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.
- (acoustics) In a speaker, the thin, semi-rigid membrane which vibrates to produce sound.
- (optics, photography) A thin opaque structure with a central aperture, used to limit the passage of light into a camera or similar device.
- (chemistry) A permeable or semipermeable membrane
1921, Wilder Dwight Bancroft, Applied Colloid Chemistry: General Theory, page 207:
- The mass of liquid transported through a porous diaphragm in a given time is directly proportional to the current.
- (construction) 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.
anatomy: sheet of muscle separating thorax from abdomen
anatomy: separating membrane or sheet of muscle
mechanics: flexible membrane
acoustics: vibrating membrane in a speaker
optics: structure with a central aperture used to limit the passage of light
chemistry: permeable or semipermeable membrane
construction: stiff floor slab etc.
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- (optics, photography) To reduce lens aperture using an optical diaphragm.
1870, D. Appleton & Co., Appletons' Annual Cyclopædia and Register of Important Events of the Year 1869, page 43:
- He employs an equatorial with an object-glass having a focal length of five metres, and which was diaphragmed down to eight centimetres.
- To act as a diaphragm, for example by vibrating.