a very naughty word
It is a shape which has two pairs of PARALLEL sides. Parallel sides - parallelogram. Get it?
A trapezoid has two parallel sides.
Trapezium
trapezoid
parallelogram
A shape with 1 pair of parallel sides is called a trapezoid. Just in case you mean 2 PAIRS of parallel sides, that is a parallelogram.
For a shape to have parallel sides it needs at least 4 sides
parallelogram
rhombus
A 25-sided shape would have no parallel sides !
A rectangle is a shape that has four sides with two parallel lines.
There is no generic name. Any polygon with 4 or more sides can have 2 parallel sides. There are also non-polygonal shapes that can have parallel sides: for example, a circle that is stretched out into a cigar shape can have two parallel sides.