From a mathematical point of view, a set is a well-defined collection of objects

Explanation

To have a meaningful discussion about sets, it is necessary to be able to identify the collection (or the set) without any confusion. This demands that there must be a rule that should guide us in identifying the elements of the set under consideration so that one can decide whether a given object belongs to the set under consideration. (Such a rule may specify a property which a single object does or does not have).