In geometry, a hypercube is an n-dimensional analogue of a square (n = 2) and a cube (n = 3). It is a closed, compact, convex figure whose 1-skeleton consists of groups of opposite parallel line segments aligned in each of the space’s dimensions, perpendicular to each other and of the same length.
An n-dimensional hypercube is also called an n-cube. The term “measure polytope” is also used, notably in the work of H.S.M. Coxeter (originally from Elte, 1912[1]), but it has now been superseded.

The hypercube is the special case of a hyperrectangle (also called an orthotope).

A unit hypercube is a hypercube whose side has length one unit. Often, the hypercube whose corners (or vertices) are the 2n points in Rn with coordinates equal to 0 or 1 is called “the” unit hypercube.

http://en.wikipedia.org/wiki/Hypercube