What is a quadrilateral with opposite sides that are parallel and congruent?

a quadrilateral is

a polygon with four sides and four vertices. Sometimes the word quadrangle is used. The interior angles add up to 360 degrees. Quadrilaterals are either simple (not self- intersecting) or complex (self-intersecting). Quadrilaterals and polygons in general, are broadly divided into two groups: convex and concave polygon.