A parallelogram is a special type of quadrilateral characterized primarily by having both pairs of opposite sides parallel and equal in length. This means:

• Both pairs of opposite sides are parallel (e.g., side AB is parallel to side CD, and side BC is parallel to side AD).
• Both pairs of opposite sides are congruent (equal in length).
• Opposite angles are equal in measure.
• Adjacent (consecutive) angles are supplementary, meaning they add up to 180 degrees.
• The diagonals bisect each other, dividing each other into two equal segments.
• Each diagonal divides the parallelogram into two congruent triangles.

These properties collectively define a parallelogram and distinguish it from other quadrilaterals. Additionally, special cases of parallelograms include rectangles (parallelograms with four right angles), rhombuses (parallelograms with four equal sides), and squares (which have both properties)