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