Definition of Diaphragm

• a mechanical device in a camera that controls size of aperture of the lens; "the new cameras adjust the diaphragm automatically"
• (anatomy) a muscular partition separating the abdominal and thoracic cavities; functions in respiration
• 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