parallelogram       
noun [ C ]  mathematics uk/ˌpær.əˈlel.ə.ɡræm/ us/ˌper.əˈlel.ə.ɡræm/
 平行四边形
a flat shape that has four sides. The two sets of opposite sides are parallel and of equal length to each other.
 Compare: trapezium (SHAPE) trapezoid (SHAPE)