diaphragms

1. a dome-shaped muscular partition separating the thorax from the abdomen in mammals. It plays a major role in breathing, as its contraction increases the volume of the thorax and so inflates the lungs.
2. a thin sheet of material forming a partition.
3. a thin contraceptive cap fitting over the cervix.
4. a device for varying the effective aperture of the lens in a camera or other optical system.

late Middle English: from late Latin diaphragma, from Greek, from dia ‘through, apart’ + phragma ‘a fence’.