In geometry, a branch of mathematics, the Steiner surfaces, discovered by Jakob Steiner, are mappings of the real projective plane into three-dimensional real projective space. They are the linear projection of the Veronese surface, an embedding of the real projective plane into five-dimensional projective space, onto three-dimensional projective space.
The Steiner surfaces can be classified into ten different types, including the Roman surface and the cross-cap.