Containment
Composition that is used to store several instances of the composited data type is referred to as containment. Examples of such containers are arrays, linked lists, binary trees and associative arrays.
In UML, containment is depicted with a multiplicity of 1 or 0..n (depending on the issue of ownership), indicating that the data type is composed of an unknown number of instances of the composited data type.
Read more about this topic: Object Composition