Di*am"e*ter (?), n. [F. diametre, L. diametros, fr. Gr. ; through + measure. See Meter.]

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.


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.

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.


© Webster 1913.