I saw several times that often some data describing certain algebraic objects, eg the set of cells of a simplical complex or a Cech cycle of a chosen coving of a variety are called *"combinatorical data"* or "encoding combinatorical data". My question is simply what is the justification of the name "combinatorial" here? what is combinatorial on these data? More generally can it be precised when a certain data describing an algebraical object is called "combinatorial"?