from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Mathematics A straight line segment passing through the center of a figure, especially of a circle or sphere, and terminating at the periphery.
- n. Mathematics The length of such a segment.
- n. Thickness or width.
- n. A unit for measuring the magnifying power of a microscope lens or telescope, equal to the number of times an object's linear dimensions are apparently increased.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any straight line between two points on the circumference of a circle that passes through the centre/center of the circle.
- n. The length of such a line.
- n. The maximum distance between any two points in a metric space
- n. The maximum eccentricity over all vertices in a graph.
from the GNU version of the Collaborative International Dictionary of English
- n. 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.
- n. A diametral plane.
- n. The length of a straight line through the center of an object from side to side; width; thickness.
- n. 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.
from The Century Dictionary and Cyclopedia
- n. In geometry, a chord of a circle or a sphere which passes through its center; in general
- n. a chord of a conic cutting it at points tangents to which are parallel;
- n. a line intersecting a quadric surface at points where the tangent planes are parallel.
- n. The length of a diameter; the thickness of a cylindrical or spherical body as measured, in the former case on a diameter of a cross-section made perpendicular to the axis, and in the latter on a line passing through the center: as, a tree two feet in diameter; a ball three inches in diameter.
- n. The diameter (see def. 2) of the object observed, taken as a convenient measure of linear magnification used in micros-copy and in telescopic work.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the length of a straight line passing through the center of a circle and connecting two points on the circumference
- n. 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)
Middle English diametre, from Old French, from Latin diametrus, from Greek diametros (grammē), diagonal (line) : dia-, dia- + metron, measure; see mē-2 in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)