From The Collaborative International Dictionary of English v.0.48 :
Polyhedron \Pol`y*he"dron\, n.; pl. E. Polyhedrons., L.
Polyhedra. [NL., fr. Gr. ? with many seats or sides; poly`s
many + ? a seat or side: cf. F. poly[`e]dre.]
1. (Geom.) A body or solid contained by many sides or planes.
[1913 Webster]
2. (Opt.) A polyscope, or multiplying glass.
[1913 Webster]