The Lebesgue covering dimension is an important dimension and one of the first dimensions investigated. It is defined in terms of covering sets, and is therefore also called the covering dimension (as well as the topological dimension).
A space has Lebesgue covering dimension 
if for every open cover of that
space, there is an open cover that refines it such that
the refinement has order at most 
. Consider how many elements of the cover contain a given
point in a base space. If this has a maximum over all the points in the base space,
then this maximum is called the order of the cover. If a space
does not have Lebesgue covering dimension 
for any 
, it is said to be infinite dimensional.
Results of this definition are:
1. Two homeomorphic spaces have the same dimension,
2. 
has dimension 
,
3. A topological space can be embedded as a closed subspace of a Euclidean space iff it is locally compact, T2, second countable, and is finite-dimensional (in the sense of the Lebesgue covering dimension), and
4. Every compact metrizable 
-dimensional topological space
can be embedded in 
.
