Rectificiation is a shape operation in which the midpoints of all of the edges of a polytope are marked, and then the vertices are cut off at those points[1]. This creates a new shape bounded by facets that are the vertex figures of the old one, as well as the recified forms of the existing facets.
For example, a cube, with triangular vertex figures and square faces, becomes a cuboctahedron, with triangular and square faces, when rectified.
If a shape is defined with a linear Coxeter-Dynkin diagram, the recitifed form can be found by ringing only the second node. This means that a rectification can be represented with the Schläfli symbol operator .