di·am·e·ter /daɪˈæmətɚ/ 名詞
1. 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.
2. 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.
Note: ☞ In an elongated object the diameter is usually taken at right angles to the longer axis.
3. 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.
Conjugate diameters. See under Conjugate.
n 1: the length of a straight line passing through the center of
a circle and connecting two points on the circumference
2: 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)