What is "cw complex"

n. (context topology English) A collection of balls of various dimensions, with higher-dimensional ones mapped along their respective boundary to lower-dimensional ones.

In topology, a CW complex is a type of topological space introduced by J. H. C. Whitehead to meet the needs of homotopy theory. This class of spaces is broader and has some better categorical properties than simplicial complexes, but still retains a combinatorial nature that allows for computation (often with a much smaller complex).