Con·ju·gate a.
 1. United in pairs; yoked together; coupled.
 2. Bot. In single pairs; coupled.
 3. Chem. Containing two or more compounds or radicals supposed to act the part of a single one. [R.]
 4. Gram. Agreeing in derivation and radical signification; -- said of words.
 5. Math. Presenting themselves simultaneously and having reciprocal properties; -- frequently used in pure and applied mathematics with reference to two quantities, points, lines, axes, curves, etc.
 Conjugate axis of a hyperbola Math., the line through the center of the curve, perpendicular to the line through the two foci.
 Conjugate diameters Conic Sections, two diameters of an ellipse or hyperbola such that each bisects all chords drawn parallel to the other.
 Conjugate focus Opt. See under Focus.
 Conjugate mirrors Optics, two mirrors so placed that rays from the focus of one are received at the focus of the other, especially two concave mirrors so placed that rays proceeding from the principal focus of one and reflected in a parallel beam are received upon the other and brought to the principal focus.
 Conjugate point Geom., an acnode. See Acnode, and Double point.
 Self-conjugate triangle Conic Sections, a triangle each of whose vertices is the pole of the opposite side with reference to a conic.
 Di·am·e·ter n.
 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.
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