Rhombohedral \Rhom`bo*he"dral\, a. (Geom. & Crystallog.) Related to the rhombohedron; presenting the form of a rhombohedron, or a form derivable from a rhombohedron; relating to a system of forms including the rhombohedron and scalenohedron. [1913 Webster] {Rhombohedral iron ore} (Min.) See {Hematite}. {Rhombohedral system} (Crystallog.), a division of the hexagonal system embracing the rhombohedron, scalenohedron, etc. [1913 Webster]