2. (Anat.) (a) A bone of the carpus at the base of the first metacarpal, or thumb. (b) A region on the ventral side of the brain, either just back of the pons Varolii, or, as in man, covered by the posterior extension of its transverse fibers.
TRAPEZOHEDRAL
Trap`e*zo*he"dral, a.
Defn: Of, pertaining to, or resembling, a trapezohedron.
TRAPEZOHEDRON Trap`e*zo*he"dron, n. Etym: [NL., from trapezium + Gr. (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.
TRAPEZOID
Trap"e*zoid, n. Etym: [Gr. trapézoïde. See Trapezium.]
1. (Geom.)
Defn: A plane four-sided figure, having two sides parallel to each other.
2. (Anat.)
Defn: A bone of the carpus at the base of the second metacarpal, or index finger.
TRAPEZOID
Trap"e*zoid, a.