Archives 101

The words “archives” and “manuscripts” denote the recorded information of individuals, organizations, and institutions. Those records are produced as the result of some activity, whether grand or mundane, and preserved because they have both an immediate and a long-term usefulness. They come in a variety of physical forms, but their intellectual significance is more critical than their format. Archives and manuscripts are not necessarily “old stuff”; they may also include valuable records of the very recent past – even yesterday. What makes the records “archives” is neither age nor appearance, but rather content, meaning, and usefulness.
James M. O'Toole. Understanding Archives and Manuscripts. (Chicago: Society of American Archivists, 1990)

The "agency or program" responsible for selecting, preserving, and making available archival materials; also referred to as an archival agency.
The "building" or part of a building where such materials are located.
Lynn Lady Bellardo and Lewis Bellardo, eds., The Glossary of Archivists, Manuscript Curators, And Records Managers. (Chicago: Society of American Archivists, 1992)