Description: Learn the term quadrilateral as well as trapezoid, parallelogram, rectangle, rhombus, and square. Created by Sal Khan. What I want to do in this video is give an overview of quadrilaterals. And you can imagine, from this prefix, or, I guess you could say, the beginning of this word involves four of something. And quadrilaterals, as you can imagine, are shapes. And we're going to be talking about two-dimensional shapes that have four sides and four vertices and four angles.*Teacher Advisor is 100% free.