Pentagon. A 5 sided figure with one pair of parallel sides and two right angles.
The question doesn't give enough information. Is it a polygon? If so, how many sides does it have? It could be 4 or any larger number. A 4-sided polygon with one pair of parallel sides is called a trapezoid (if you're American) or a trapezium (if you're British). (I don't know about other dialects of English.)
It sounds like the shape that you are talking about is a right trapezoid. It only has one pair of parallel sides but its two left angles are 90 degrees.
The shape you are looking for is a quadrilateral. If you have a square, all angles MUST be right angles. A parallelogram can also have 4 equal sides in length and parallel sides, but a parallelogram doesn't have right angles.
Rhombus
A parallelogram has both pairs of opposite sides parallel but no right angles. A special kind of parallelogram is a rhombus which has all its sides of equal length
Rectangle
trapizoid
A shape with parallel sides but no right angles is called a parallelogram
A shape with opposite sides parallel and of the same length and four right angles is a rectangle.
A rectangle has two right angles and parcel sides
A rhombus has 4 sides of equal length, opposing parallel sides, and no right angles
A rhombus
A parallelogram.
parallelogram
A shape that has exactly 4 sides, 2 right angles and one pair of parallel sides is a rectangle. ~T
A square
A square
A square
It is a square