Main Entry: di·a·phragm

Pronunciation: \ˈdī-ə-ˌfram\

Function: noun

1 : a body partition of muscle and connective tissue ; specifically : the partition separating the chest and abdominal cavities in mammals—see pelvic diaphragm, urogenital diaphragm
2 : a device that limits the aperture of a lens or optical system

[diaphragm illustration]

3 : a molded cap usually of thin rubber fitted over the uterine cervix to act as a mechanical contraceptive barrier