(noun, verb)


1. a mechanical device in a camera that controls size of aperture of the lens

- the new cameras adjust the diaphragm automatically

Similar word(s): stop

Definition categories: man–made

2. (anatomy) a muscular partition separating the abdominal and thoracic cavities; functions in respiration

Similar word(s): midriff

Definition categories: body, membrane, musculature

3. a contraceptive device consisting of a flexible dome-shaped cup made of rubber or plastic; it is filled with spermicide and fitted over the uterine cervix

Similar word(s): pessary

Definition categories: man–made, contraceptive, preventative, preventive

4. electro-acoustic transducer that vibrates to receive or produce sound waves

Definition categories: man–made, disc, disk


1. (optics, photography) To reduce lens aperture using an optical diaphragm.

2. To act as a diaphragm, for example by vibrating.