In geometry, a bicone or dicone (from , and Greek: di-, both meaning "two") is the three-dimensional surface of revolution of a rhombus around one of its axes of symmetry. Equivalently, a bicone is the surface created by joining two congruent right circular cones at their bases. A bicone has circular symmetry and orthogonal bilateral symmetry.
For a bicone with radius and half-height , the volume is
and the surface area is
where
is the slant height.