n. [ L. diaphragma, Gr. &unr_;, fr. &unr_; to fence by a partition wall;
Diaphragm pump,
a. [ Cf. F. diaphragmatique. ] Pertaining to a diaphragm;
. An adjustable diaphragm, reminiscent of the iris of the eye in its action, by which the diameter of an approximately circular opening may be controlled, as for regulating the aperture of a lens; it consists of a number of movable thin curved plates fastened at regular intervals around the inside of a ring, the positions of which are simultaneously adjusted by a single knob on the outside of the lens. It is used in cameras and microscopes. [ Webster 1913 Suppl. +PJC ]