n.A thing that can be distinguished from a group and that is complete in itself.
NotesAn item may consist of several pieces2 but is treated as a whole. For example, a letter may have several physically discrete pages but is treated as an item because of its content. A decision about the boundaries of an item is sometimes ambiguous; a photograph album may be considered an item, and the individual photographs within the album may also be considered items. Items are generally considered to be the smallest archival unit.