great rhombicuboctahedron noun1 •An Archimedean solid that is isogonal and has twenty-six regular faces (twelve square, eight hexagonal and six octagonal).Figure 244 — the structure for this complicated design is the great rhombicuboctahedron, which consists of octagonal, hexagonal, and square faces. — 1977 formsgreat rhombicuboctahedra · great rhombicuboctahedrons