资料来源 : pyDict

有三面的

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Trihedral \Tri*he"dral\, a. [See {Trihedron}.] (Geom.)
   Having three sides or faces; thus, a trihedral angle is a
   solid angle bounded by three plane angles. [Written also
   {triedral}.]