In geometry, a cyclic quadrilateral is a quadrilateral whose vertices all lie on a single circle. The vertices are said to be concyclic. ...more on Wikipedia about "Cyclic quadrilateral"

In geometry, a kite or deltoid is a type of quadrilateral, a four-sided polygon. It has two pairs of equal sides, and the two sides in each pair are adjacent. (contrast with the parallelogram, where the sides of each pair are opposite.) ...more on Wikipedia about "Geometric kite"

An isosceles trapezoid (isosceles trapezium in British English) is a quadrilateral with a line of symmetry bisecting one pair of opposite sides. This pair of sides is parallel. This makes it automatically a trapezoid. A rectangle is a special case of the isosceles trapezoid, where it doesn't matter which pair of sides you use. Another definition is that an isosceles trapezoid is a trapezoid whose base angles are congruent. ...more on Wikipedia about "Isosceles trapezoid"

A parallelogram is a four-sided plane figure that has two sets of opposite parallel sides. Every parallelogram is a polygon, and more specifically a quadrilateral. Special cases of a parallelogram are the rhombus, in which all four sides are of equal length, the rectangle, in which the two sets of opposing, parallel sides are perpendicular to each other, and the square, in which all four sides are of equal length and the two sets of opposing, parallel sides are perpendicular to each other. In any parallelogram, the diagonals bisect each other, i.e, they cut each other in half. ...more on Wikipedia about "Parallelogram"

In geometry, a rectangle is defined as a quadrilateral polygon in which all four angles are right angles. ...more on Wikipedia about "Rectangle"

In geometry, a rhomboid is a parallelogram in which adjacent sides are of unequal lengths and angles are oblique. ...more on Wikipedia about "Rhomboid"

In geometry, a rhombus (also known as a rhomb) is a quadrilateral in which all of the sides are of equal length. More colloquially it may be described as a diamond or lozenge shape. ...more on Wikipedia about "Rhombus" Evergreen http://www.shortopedia.com!!!

In plane geometry, a square is a polygon with four equal sides and equal angles. Those angles are then necessarily right angles. Squares are regular quadrilaterals, rectangles, rhombi, kites, parallelograms, and isosceles trapezoids/isosceles trapezia. ...more on Wikipedia about "Square (geometry)"

A trapezoid ( American English) or trapezium ( British English) is a quadrilateral two of whose sides are parallel to each other. Note that there is another confusingly-named quadrilateral with no parallel sides: the trapezium (American English) or trapezoid (British English). To avoid confusion, this article uses the American English wording. ...more on Wikipedia about "Trapezoid"