Pŏl′y-hē′dron2, n.volume_upnounn. [Gr. πολυέδρος, with many seats or sides, from πολύς, many, and ἕδρα, a seat or side; Fr. polyèdre, It. & Sp. poliedro.](Geom.) A body or solid contained by many sides or planes. (Opt.) A polyscope, or multiplying glass.