\begin{definition}[Definition:Dimension (Topology)/Locally Euclidean Space]
Let $M$ be a locally Euclidean space. 
Let $\struct {U, \kappa}$ be a coordinate chart such that: 
:$\kappa: U \to \map \kappa U \subseteq \R^n$
for some $n \in \N$.
Then the natural number $n$ is called the '''dimension of $M$'''.
\end{definition}