In mathematics, the term "collection" is generally used to mean a multiset, i.e., a set in which order is ignored but multiplicity is significant.
Collection
See also
Aggregate, Multiset, SetExplore with Wolfram|Alpha
References
Kestelman, H. Modern Theories of Integration, 2nd rev. ed. New York: Dover, p. 3, 1960.Referenced on Wolfram|Alpha
CollectionCite this as:
Weisstein, Eric W. "Collection." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Collection.html