From hepta- + hexahedral. heptahexahedral (not comparable) Having seven ranges of faces one above another, each range containing six faces....
+ -hedral. hexahedral (not comparable) Having six plane surfaces. heptahexahedral hexahedrally tetrahexahedral hexahedron having six plane surfaces...
heptahedron heptahelical heptahelicene heptalemma heptaverine heptahex heptahexahedral heptahydrate heptahydrated heptahydric heptahydride heptahydroxy heptairon...