Definify.com
Webster 1913 Edition
Tetragon
Tet′ra-gon
,Noun.
1.
(Geom.)
A plane figure having four sides and angles; a quadrangle, as a square, a rhombus, etc.
2.
(Astrol.)
An aspect of two planets with regard to the earth when they are distant from each other ninety degrees, or the fourth of a circle.
Hutton.
Webster 1828 Edition
Tetragon
TET'RAGON
,Noun.
1.
In geometry, a figure having four angles; a quadrangle; as a square, a rhombus, &c.2.
In astrology, an aspect of two planets with regard to the earth, when they are distant from each other ninety degrees, or the fourth of a circle.