Definition of pyritohedron in US English:

pyritohedron

noun

  • A twelve-sided polyhedron with pentagonal faces, which is particularly common in crystals of pyrite.

Origin

Mid 19th century; earliest use found in John Joseph Griffin (1802–1877), chemist, author, and business manager. From pyrito- + -hedron.

Pronunciation

pyritohedron

/pɪˌrʌɪtəʊˈhiːdrən/