PENTAHEDRON Meaning of PENTAHEDRON in English [ ˌpɛntə'hi:dr(ə)n , -'hɛd- ]■ noun ( plural pentahedra -drə or ~s ) a solid figure with five plane faces.Derivativespentahedral adjective Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004