gon-, gonio-, -gon, -gonal, -gonally, -gony

(Greek: corner, bend, angle)

agonic (adjective), more agonic, most agonic
Characteristic of not forming an angle; having no angle: The line indicating the perimeter of a circle is an agonic line.
decagon
diagon
diagonal
1. Extending between nonadjacent angles in a polygon figure.
2. Having slanting marks, lines, etc.
dodecagon
enneagon
goniometer
goniometry
hendecagonal (adjective), more hendecagonal, most hendecagonal
In the form or in the shape of a multiple angles having eleven sides.
heptagon (s) (noun), heptagons (pl)
A geometric shape with seven angles and seven sides: "The students were learning about heptagons in their math class."
hexagon
isogonic
Having , or pertaining to, equal angles.
nonagon, nonagonal; enneagon
A polygon having nine angles and nine sides.
octagon
orthogonal
1. Having or determined by right angles; perpendicular.
2. An area of a computer display in which units of distance are the same horizontally and vertically so that there is no distortion.