It can be but it need not be.
A trapezoid.
It is a trapezoid which has 1 pair of opposite parallel sides of different lengths
A quadrilateral with only one pair of parallel sides is a trapezoid (U.K. trapezium)
It is a trapezoid that has only one pair of opposite parallel lines of different lengths.
square
A quadrilateral with one pair of parallel lines would be a trapezoid. : P
Any four-sided shape is a Quadrilateral. Square, Rectangle, Parallelogram, rhombus, trapezoid etc. It may have no parallel sides as in a kite, 1 parallel side as in trapezoid or 2 parallel sides as in parallelogram.
The Rectangle and the Parallelogram both have 2 pairs of parallel sides. The Trapezium has 4 sides but only 2 are a parallel pair. The Kite has 2 pairs of equal sides but none parallel. The limits is an irregular quadrilateral with no side equal or parallel to another.
A trapezoid is a quadrilateral with at least one pair of parallel sides. This pair of parallel sides are known as the bases of the trapezoid. The other two sides are called the legs, and they are not parallel to each other. So, a trapezoid has exactly one pair of parallel sides.
A trapezoid
a trapezoid