par·al·lel·e·pi·ped 
(păr′ə-lĕl′ə-pīpĭd, -pĭpĭd)
(păr′ə-lĕl′ə-pīpĭd, -pĭpĭd)n.
A solid with six faces, each a parallelogram and each being parallel to the opposite face.
[Greek parallēlepipedon : parallēlos, parallel; see PARALLEL + epipedon, plane surface, from neuter sing. of epipedos, level (epi-, epi- + pedon, ground; see ped- in the Appendix of Indo-European roots).]
parallelepipedrectangular parallelepiped