A collection template describes the Pattern Expression, or the used patterns that describe the collection.
A collection description is the formalization combined with the Pattern Expression, that documents the used patterns and the rationalizations upon which the template is based.
So the abstraction layers is:
Pattern expression -- The general, and yet formalized, description of the process and thoughts that forms the basis of the collection architecture. with references to a series of connected patterns.
Collection description -- A short, more technical, description of the elements that form the collection.
Technical/Collection formalization -- The actual DOMS collection described. This should be represented in the best possible way, it can be a diagram, it can also be represented by a XML file, or parts thereof. Other descriptive measures should also be considered.
Pattern expression
Write your pattern expression here
Collection description
Sum up the elements in the collection here
Technical
be concrete and go into detail, especially if the collection is complex or of a special nature.