An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

A combining form meaning "face" used in the names of geometrical solid figures having the form or number of faces specified by the initial element.

N.L., from Gk -edron, from hedra "seat, base, chair, face of a geometric solid," from PIE root *sed- "to → sit."

Dimé, from dim, → face.

A figure formed by two intersecting planes.

→ di-; → -hedron.

A geometric solid with eight sides.

→ octa-, oct-; → -hedron.

1) Geometry: A three-dimensional figure formed by several → polygons.
2) A set P ⊆ ℜⁿ is a polyhedron if there is a system of finitely many unequalities Ax ≤ b such that P = {x ∈ ℜⁿ | Ax ≤ b}.

→ poly-; → hedron.

A solid figure having four plane faces.

→ tetra-; → -hedron.