Available Definitions:
1) n. - A solid whose bases or ends are any similar, equal, and parallel plane figures, and whose sides are parallelograms.
2) n. - A transparent body, with usually three rectangular plane faces or sides, and two equal and parallel triangular ends or bases; -- used in experiments on refraction, dispersion, etc.
3) n. - A form the planes of which are parallel to the vertical axis. See Form , n., 13.