Online Catalog Data Model
The smallest intellectually indivisible archival unit (e.g. a letter, memorandum, report, leaflet, or photograph).
For example, the item "Record Jacket for the Release of Elvis Presley's 'Too Much' and 'Playing for Keeps'" is one item (or document) in the file unit "William D. Beasley and Jean Norris Beasley v. Southern Belle Music, Incorporated et al., Civil Action No. 2390."