D defs.my
Entry 2 senses Webster, 1913

Tetragon

· Tet·ra·gon · IPA /ˈtɛ.tɹə.ɡɒn/
01 n. A plane figure having four sides and angles; a quadrangle, as a square, a rhombus, etc.
  1. 1.
    A plane figure having four sides and angles; a quadrangle, as a square, a rhombus, etc.(Geom.)
  2. 2.
    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.(Astrol.)