• (a.) Having all the planes required by complete symmetry, -- in opposition to hemihedral.
Hol`o·he'dral adjective [ Holo- + Greek ... seat, base, from ... to sit.] (Crystallog.) Having all the planes required by complete symmetry, -- in opposition to hemihedral . 
(of a crystal) having all the planes or faces required by the maximum symmetry of the system to which it belongs.