n.
Pronunciation: d ī - ' a-m ə -t ə r
Function: noun
Etymology: Middle English diametre, from Middle French, from Latin diametros, from Greek, from dia- + metron measure ― more at MEASURE
Date: 14th century
1 : a chord passing through the center of a figure or body
2 : the length of a straight line through the center of an object
3 : a unit of enlargement used with a number to indicate magnification by a lens or optical system <an object one millimeter wide magnified 40 diameter s appears 40 millimeters wide>
– di · am · e · tral \ - ' a-m ə -tr ə l \ adjective