chival unit can be a fonds, series, file, item or variation thereof, depending on institutional standards.
A unit may be divided into sub-units for the purposes of archival description. The smallest (and therefore indivisible)
archival unit is the item. [Archives] 
v., To save digital data, documents, and records, typically those that are not current, offline. [Computer and Information Sciences] 
v., To transfer records from the individual or office of creation to a repository authorized to appraise, preser