In geometry, a **7-orthoplex**, or 7-cross polytope, is a regular 7-polytope with 14 vertices, 84 edges, 280 triangle faces, 560 tetrahedron cells, 672 5-cells *4-faces*, 448 *5-faces*, and 128 *6-faces*.

It has two constructed forms, the first being regular with Schläfli symbol {3^{5},4}, and the second with alternately labeled (checkerboarded) facets, with Schläfli symbol {3,3,3,3,3^{1,1}} or Coxeter symbol **4**_{11}.

It is a part of an infinite family of polytopes, called cross-polytopes or *orthoplexes*. The dual polytope is the 7-hypercube, or hepteract.

**Heptacross**, derived from combining the family name *cross polytope* with *hept* for seven (dimensions) in Greek.
**Hecatonicosoctaexon** as a 128-facetted 7-polytope (polyexon).
There are two Coxeter groups associated with the 7-orthoplex, one regular, dual of the hepteract with the C_{7} or [4,3,3,3,3,3] symmetry group, and a half symmetry with two copies of 6-simplex facets, alternating, with the D_{7} or [3^{4,1,1}] symmetry group. A lowest symmetry construction is based on a dual of a 7-orthotope, called a **7-fusil**.

Cartesian coordinates for the vertices of a 7-orthoplex, centered at the origin are

(±1,0,0,0,0,0,0), (0,±1,0,0,0,0,0), (0,0,±1,0,0,0,0), (0,0,0,±1,0,0,0), (0,0,0,0,±1,0,0), (0,0,0,0,0,±1,0), (0,0,0,0,0,0,±1)

Every vertex pair is connected by an edge, except opposites.