Definition of pentagonohedron in US English:

pentagonohedron

noun

rare
  • A solid figure having pentagonal plane faces.

Origin

Late 19th century; earliest use found in Nevil Story-Maskelyne (1823–1911), mineralogist. From pentagon + -o- + -hedron.

Pronunciation

pentagonohedron

/ˌpɛntəɡ(ə)nəˈhiːdr(ə)n/