The mathematical term for a shape with four sides is a quadrilateral. Quadrilaterals can take various forms, including squares, rectangles, trapezoids, and parallelograms. Each type has distinct properties, such as the lengths of sides and the measures of angles. The sum of the interior angles of any quadrilateral is always 360 degrees. Quadrilaterals are a fundamental concept in geometry and are encountered in numerous practical applications, from architectural design to art. Understanding the characteristics of quadrilaterals is essential in both theoretical mathematics and real-world problem-solving.