The elongated dodecahedron, also known as the extended rhombic dodecahedron and rhombo-hexagonal dodecahedron, is a space-filling polyhedron
and primary parallelohedron bounded by
eight rhombi of angle (at the poles) and an equatorial
zone of four equilateral hexagons having opposite
angles of ,
with the remaining four angles equal (Coxeter 1973, pp. 29-30 and 257).

The elongated dodecahedron can be constructed by stretching a rhombic dodecahedron until the middle ring of rhombi become regular hexagons. Note that
in this case, the term "elongated" refers to stretching of some of the
existing faces as opposed to insertion of additional faces, the latter meaning of
which is used in the naming of Johnson solids.

Coxeter, H. S. M. Regular Polytopes, 3rd ed. New York: Dover, 1973.Fedorov, E. S.
"Elemente der Gestaltenlehre." Mineralogicheskoe obshchestvo Leningrad
(Verhandlungen der Russisch-Kaiserlichen Mineralogischen Gesellschaft zu St. Petersburg21,
1-279, 1885.Tutton, A. E. H. Crystallography
and Practical Crystal Measurement. London, pp. 567 (Fig. 448) and
723 (Fig. 585), 1922.