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. * Collection formalization -- the actual DOMS collection, this can be represented by a XML file, or parts thereof, in the documentation.