n.; pl. E. Decahedrons L. Decahedra [ Pref. deca- + Gr. 'e`dra a seat, a base, fr. 'e`zesqai to sit: cf. F. décaèdre. ] (Geom.) A solid figure or body inclosed by ten plane surfaces. [ Written also, less correctly, decaedron. ] [ 1913 Webster ]