tetartohedral
adjective
te·tar·to·he·dral te-ˌtär-tə-ˈhē-drəl 
of a crystal
: having one fourth the number of planes required by complete symmetry compare hemihedral, holohedral
Word History
Etymology
Greek tetartos fourth; akin to Greek tettares four — more at four
First Known Use
circa 1858, in the meaning defined above