Is a quadrilateral always a parallelogram?

No, a quadrilateral is not always a parallelogram. A quadrilateral is any four-sided polygon. A parallelogram is a specific type of quadrilateral that has two pairs of parallel sides. While all parallelograms are quadrilaterals, not all quadrilaterals are parallelograms. Other types of quadrilaterals include rectangles, squares, trapezoids, and rhombuses.