What is a difference between a square and a trapezoid? A square has 4 sides but a trapezoid does not. A trapezoid is a quadrilateral but a square is not. A trapezoid must have 4 angles but a square does not. A square must have 2 pairs of parallel sides but a trapezoid does not.

Step 1 ：A square is a quadrilateral with all sides equal and all angles equal to 90 degrees: \(4\) sides, \(4\) angles, and \(2\) pairs of parallel sides.

Step 2 ：A trapezoid is a quadrilateral with at least one pair of parallel sides: \(4\) sides, \(4\) angles, and \(1\) pair of parallel sides.

Step 3 ：\boxed{\text{A square must have 2 pairs of parallel sides but a trapezoid does not.}}