Main Entry: di·am·e·ter

Pronunciation: \dī-ˈam-ət-ər\

Function: noun

1 : a unit of magnification for an optical instrument equal to the number of times the linear dimensions of an object are apparently increased <a microscope magnifying 60 diameters>
2 : one of the maximal breadths of a part of the body <the transverse diameter of the inlet of the pelvis>