A quadrilateral is a 2D polygon with four edges and four vertices.
A rectangle is a quadrilateral with four right angles.
A square is a rectangle that has four equal sides.
A parallelogram is a quadrilateral with two pairs of parallel sides.
An Isosceles trapezoid is a quadrilateral with a line of symmetry bisecting one pair of opposite sides. It's a trapezoid in which both legs and base angles are of equal measure.
A rhombus is a quadrilateral whose sides all have the same length.