Diaphragm

(di1 ’ -ah-fram) [did, acro ; <ppd-) ua, wall]. I. The musculomembranous partition that separates the thorax and abdomen. It is the chief muscle of respiration. 2. A thin septum, such as is used in dialysis. 3. In a microscope, a perforated plate placed between the mirror and object to regulate the amount of light that is to pa through the object. 226