A four-sided polygon with opposite sides parallel and all sides congruent is a square.
Any polygon with an even number of sides can have opposite sides that are congruent and parallel.
A four-sided polygon with all sides parallel and congruent is a rhombus. If all the angles are equal, it is a special case of a rhombus called a square.
A general quadrilateral is a four sided polygon with no parallel sides and no congruent sides.
A rectangle is a quadrilateral with opposite sides parallel and congruent and four right angles. If all four sides are congruent, it is a square.
A polygon with all congruent sides is a regular polygon.
Rhombus (or square).
A polygon with five congruent sides is a pentagon.
A polygon with all sides congruent is a square.
A regular polygon is a polygon with congruent sides and interior angles.