a polygon that is equiangular and equilateral

STRAIGHT LINE FROM THE CENTER TO THE CIRCUMFERENCE OF A CIRCLE OR SPHERE.

a plane figure with at least three straight sides and angles, and typically five or more.

The size of a surface.

a four-sided plane rectilinear figure with opposite sides parallel.

a straight line joining two opposite corners of a square, rectangle, or other straight-sided shape.

a quadrilateral whose four sides can be grouped into two pairs of equal-length sides

a regular quadrilateral, which means that it has four equal sides and four equal angles

any parallelogram with equal sides, including a square.

a plane figure with four straight sides and four right angles, especially one with unequal adjacent sides, in contrast to a square.

a four-sided figure

A FOUR-SIDED FIGURE

a convex quadrilateral with a line of symmetry bisecting one pair of opposite sides