obturator

plural obturators

1. medicineAn object used to obstruct a hole, such as a fissure of the palate.
2. anatomyThe membrane vessels, etc. that close the obturator foramen, or thyroid foramen, a large opening or fenestra in the anterior part of the hip bone.
3. engineeringA valve closure member (disk, gate, plug, etc.).

   Obturators, held down by compressed air, close the pipe giving direct access from the h.p. exhaust to the l.p. steam chest, and so prevent compound working; […].

   1952 December, 'Mercury', “Modern French Locomotive Performance”, in Railway Magazine, page 803

4. engineeringAny device for preventing the escape of gas through the breech mechanism of a breech-loading gun; a gas check.
5. artsA camera shutter.