pentagon-dodecahedron
/ˌpɛntəɡ(ə)nˌdəʊdɛkəˈhiːdr(ə)n/Chiefly Crystallography
noun
A dodecahedron which has twelve pentagonal faces but is not a regular dodecahedron; a solid figure or structure of this form.
Origin
Late 19th century; earliest use found in Nevil Story-Maskelyne (1823–1911), mineralogist. From pentagon + dodecahedron.