The term "*n*-dimensional Euclidean space" is usually abbreviated to "Euclidean *n*-space", or even just "*n*-space". Euclidean *n*-space is denoted by *E*^{ n}, although **R**^{n} is also used (with the metric being understood). *E*^{ 2} is called the **Euclidean plane**.

By definition, *E*^{ n} is a metric space, and is therefore also a topological space. It is the prototypical example of an *n*-manifold, and is in fact a differentiable *n*-manifold. For *n* ≠ 4, any differentiable *n*-manifold that is homeomorphic to *E*^{ n} is also diffeomorphic to it. The surprising fact that this is not also true for *n* = 4 was proved by Simon Donaldson in 1982; the counterexamples are called exotic (or fake) 4-spaces.

Much could be said about the topology of *E*^{ n}, but that will have to wait until a later revision of this article. One important result, Brouwer's invariance of domain, is that any subset of *E*^{ n} which is homeomorphic to an open subset of *E*^{ n} is itself open. An immediate consequence of this is that *E*^{ m} is not homeomorphic to *E*^{ n} if *m* ≠ *n* -- an intuitively "obvious" result which is nonetheless not easy to prove.

Euclidean *n*-space can also be considered as an *n*-dimensional real vector space, in fact a Hilbert space, in a natural way.

See also: Euclidean geometry.