Noun
hypersurface (plural hypersurfaces)
(mathematics) A n-dimensional surface in a space (often a Euclidean space) of dimension n+1
More commonly a space-like hypersurface is defined technically as a surface such that the normal vector at every point is time-like, but the definition above may be somewhat more intuitive. Source: Internet
;Sectioning Just as a slice through a polyhedron reveals a cut surface, so a slice through a 4-polytope reveals a cut "hypersurface" in three dimensions. Source: Internet
The gradient of F is then normal to the hypersurface. Source: Internet