Visual Basic for Applications Reference
A Collection object is an ordered set of items that can be referred to as a unit.
The Collection object provides a convenient way to refer to a related group of items as a single object. The items, or members, in a collection need only be related by the fact that they exist in the collection. Members of a collection don't have to share the same data type.
A collection can be created the same way other objects are created. For example:
Dim X As New Collection
Once a collection is created, members can be added using the Add method and removed using the Remove method. Specific members can be returned from the collection using the Item method, while the entire collection can be iterated using the For Each...Next statement.