Metadata Standards

“Metadata elements grouped into sets designed for a specific purpose, e.g., for a specific domain or a particular type of information resource, are called metadata schemes.

"For every element the name and the semantics (the meaning of the element) are specified. Content rules (how content must be formulated), representation rules (e.g., capitalization rules), and allowed element values (e.g., from a controlled vocabulary) can be specified optionally. Some schemes also specify in which syntax the elements must be encoded, in contrast to syntax independent schemes. Many current schemes use Standards Generalized Mark-up Language (SGML) or XML to specify their syntax (NISO, 2004). Metadata schemes that are developed and maintained by standard organizations (such as ISO) or organizations that have taken on such responsibility (such as the Dublin Core Metadata Initiative) are called metadata standards.” - Wikipedia