diameter Meaning, Definition & Usage

noun the length of a straight line passing through the center of a circle and connecting two points on the circumference
diam.
noun a straight line connecting the center of a circle with two points on its perimeter (or the center of a sphere with two points on its surface)

F. diamètre, L. diametros, fr. Gr. through + measure. See Meter.

(Geom.) (a) Any right line passing through the center of a figure or body, as a circle, conic section, sphere, cube, etc., and terminated by the opposite boundaries; a straight line which bisects a system of parallel chords drawn in a curve. (b) A diametral plane.
The length of a straight line through the center of an object from side to side; width; thickness; as, the diameter of a tree or rock. ✍ In an elongated object the diameter is usually taken at right angles to the longer axis.
(Arch.) The distance through the lower part of the shaft of a column, used as a standard measure for all parts of the order. See Module.