metadata

Metadata can be defined literally as "data about data," but the term is normally understood to mean structured data about digital (and non-digital) resources that can be used to help support a wide range of operations. These might include, for example, resource description and discovery, the management of information resources (including rights management) and their long-term preservation. In the context of digital resources, there exists a wide variety of metadata formats. Viewed on a continuum of increasing complexity, these range from the basic records used by robot-based Internet search services, through relatively simple formats like the Dublin Core Metadata Element Set (DCMES) and the more detailed Text Encoding Initiative (TEI) header and MARC formats, to highly specific formats like the FGDC Content Standard for Digital Geospatial Metadata, the Encoded Archival Description (EAD) and the Data Documentation Initiative (DDI) Codebook. (Excerpt from this source)