A parallelogram is a quadrilateral (a four-sided polygon) with two pairs of parallel sides. This means that opposite sides of a parallelogram are parallel and of equal length.
Additionally, opposite angles of a parallelogram are also equal in measure. Parallelograms come in various shapes, including rectangles and squares, which are special types of parallelograms with additional properties (e.g., right angles).
They are commonly encountered in geometry and have properties that make them useful for various calculations and geometric constructions.