A "collection" refers to a group of materials (irregardless of format) with some unifying characteristic. Within the context of special collections in libraries, the term refers to materials actively assembled with intent by a person, organization or repository from a variety of sources.
This is different from an archives, which is the organic accumulation of records and documents as the by-product of activities, where the origin and provenance and arrangment reflect their original order.
See the SAA glossary of terms for more information.
Available here: http://www.archivists.org/glossary/index.asp
Below are brief summaries of the various special collections held by the Clara Thomas Archives & Special Collections. They include scarce and rare publications as well as important association copies related to the particular intellectual devlopment of a public figure.