In geometry, a **tesseract**, also called an **8-cell** or **regular octachoron** or **cubic prism **or** 4-cube** or **hypercube**, is the four-dimensional analog of the cube. The tesseract is to the cube as the cube is to the square. Just as the surface of the cube consists of 6 square faces, the hypersurface of the tesseract consists of 8 cubical cells. The tesseract is one of the six convex regular 4-polytopes. The Tesseract is a Polychoron.

A generalization of the cube to dimensions greater than three is called a "hypercube", "*n*-cube" or "measure polytope". The tesseract is the **four-dimensional hypercube**, or **4-cube**.