18081809

18081809 is an eight-digit numeric string that does not correspond to a standard calendar date, but is sometimes used as a compact code representing a two-year span: 1808 through 1809. In archival, bibliographic, and data-management contexts, such concatenated year codes appear as identifiers that group items associated with a short historical interval.

In this scheme, the first four digits indicate the starting year (1808) and the last four indicate the ending year (1809). The format is machine-friendly and can be embedded in file names, catalog numbers, or dataset keys. It is not a universal standard; different systems may store the same information as 1808–1809, 1808 1809, or as separate start and end fields.

Potential uses include indexing a collection of documents published in or relating to the period 1808–1809, or tagging inventory items, events, or publications tied to those years. Because it is context-dependent, 18081809 should be interpreted with the associated metadata to avoid ambiguity.

See also: 1808, 1809, year-range coding, data identifiers.