Meaning

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

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

noun 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

originFrom Middle English diafragma, Ancient Greek διάφραγμα (diáphragma, “partition”), from διά (diá, “across”) and φράγμα (phrágma, “barrier”), from the verb φράσσω (phrássō). First attested in the late 14th century.

Etymology from Wiktionary, CC BY-SA 3.0