, in Geometry, a quadrangle, or a figure having 4 angles. Such as a square, a parallelogram, a rhombus, and a trapezium. It sometimes also means peculiarly a square.
Tetragon, in Astrology, denotes an aspect of two planets with regard to the earth, when they are distant from each other a 4th part of a circle, or 90 degrees. The Tetragon is expressed by the character □, and is otherwise called a square or quartile aspect.
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Entry taken from A Mathematical and Philosophical Dictionary, by Charles Hutton, 1796.
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