enneadecahedron

From enneadeca- +‎ -hedron.

enneadecahedron (plural enneadecahedra or enneadecahedrons) (rare)

1. (geometry) A polyhedron with nineteen faces.
   • 1970, Research Paper, page 22:

     Guy [24] and Knowlton have independently discovered a uniform unistable enneadecahedron.

   • 1980, Crux Mathematicorum, pages 28, 29:

     Klamkin noted that [1] contains an improved solution by R.K. Guy to the polyhedron problem, consisting of a doubly truncated 17-sided convex prism, making it an enneadecahedron (19 faces). […] Ogilvy referred to his book [4], where he describes Guy's enneadecahedron.

   • 1990, Murray S. Klamkin, Problems in Applied Mathematics: Selections from SIAM Review, Society for Industrial and Applied Mathematics, →ISBN, page 478:

     Our solid is a 17-sided prism, half of whose section is illustrated in Fig. 5, truncated obliquely as in the side view of Fig. 6, so it is an enneadecahedron.