Par`al*lel`o*pi"ped (?), n. [Gr. &?; a body with parallel surfaces; &?; parallel + &?; a plane surface, &?; on the ground, or level with it, level, flat; &?; on + &?; the ground: cf. F. parallélopipède.] (Geom.) A solid, the faces of which are six parallelograms, the opposite pairs being parallel, and equal to each other; a prism whose base is a parallelogram.