plane figure, two-dimensional figure - a two-dimensional shape

isogon - an equiangular polygon

convex polygon - a polygon such that no side extended cuts any other side or vertex; it can be cut by a line in at most two points

concave polygon - a polygon such that there is a straight line that cuts it in four or more points

quadrangle, quadrilateral, tetragon - a four-sided polygon

triangle, trigon, trilateral - a three-sided polygon

pentagon - a five-sided polygon

hexagon - a six-sided polygon

heptagon - a seven-sided polygon

octagon - an eight-sided polygon

nonagon - a nine-sided polygon

decagon - a polygon with 10 sides and 10 angles

undecagon - an eleven-sided polygon

dodecagon - a twelve-sided polygon

spherical polygon - a figure on the surface of a sphere bounded by arcs of 3 or more great circles