The 
-skeleton of a simplicial
complex 
,
where 
is a nonnegative
integer, is the simplicial subcomplex
consisting of all simplices of 
of dimension at most 
, denoted 
(Munkres 1993).
For a CW-complex 
, the 
-skeleton
is the union of its cells of dimension
at most 
.
The special case 
is the 1-skeleton (Hatcher 2002).
