\Trap`e*zo*he"dron\, n. [NL., from trapezium + Gr.
? seat, base, fr. ? to sit.] (Crystalloq.)
(a) A solid bounded by twenty-four equal and similar
    trapeziums; a tetragonal trisoctahedron. See the Note
    under {Trisoctahedron}.
(b) A tetartohedral solid of the hexagonal system, bounded by
    six trapezoidal planes. The faces of this form are common
    on quartz crystals.