diaphragm - noun

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

(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

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

diaphragm - thesaurus

midriff   pessary   stop