A parallelogram is a simple quadrilateral with two pairs of parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of equal measure.
A Four-Sided plane rectilinear figure with opposite sides parallel.
In geometry, there is a name for convex polyhedrons that are regular, of which there are 5 types. Generically, what kind of solid are they called?