Which type of quadrilateral has both pairs of opposite sides parallel?

A quadrilateral that has both pairs of opposite sides parallel is classified as a parallelogram. This definition is fundamental in geometry and encompasses various specific types of quadrilaterals, such as rectangles, squares, and rhombuses, all of which are indeed parallelograms because they meet the criteria of having two pairs of parallel sides.

Parallelograms exhibit unique properties that arise from this characteristic, including that the opposite sides are equal in length and the opposite angles are equal. Additionally, the diagonals of a parallelogram bisect each other, which is another important property.

While rectangles, squares, and rhombuses also have both pairs of opposite sides parallel, they fall under the broader category of parallelograms. Thus, identifying a quadrilateral simply having both pairs of opposite sides parallel is best described by the more general term "parallelogram." This demonstrates a clear understanding of the classification of quadrilaterals within geometry.