What is (a) Consisting of two hexagonal parts united; thus, a dihexagonal pyramid is composed of two hexagonal pyramids placed base to base. (b) Having twelve similar faces; as, a dihexagonal prism called?

dihexagonal — (a) Consisting of two hexagonal parts united; thus, a dihexagonal pyramid is composed of two hexagonal pyramids placed base to base. (b) Having twelve similar faces; as, a dihexagonal prism. (Webster's 1913.)

Sources