Dublin Core

The Dublin Core. The Dublin Core (DC) defines a set of metadata terms which is aimed at describing properties of published documents.

The Dublin Core Metadata Initiative (DCMI) has written multiple specifications:
 * The Dublin Core Metadata Element Set, as defined at http://purl.org/dc/elements/1.1/
 * Other Elements and Element Refinements, as defined at http://purl.org/dc/terms/
 * Encoding Schemes, as defined at http://purl.org/dc/terms/
 * The DCMI Type Vocabulary, as defined at http://purl.org/dc/dcmitype/

Use in RDF documents
Dublin Core was primarily designed to be used in RDF documents. It allows you to make statements like:   John Doe 

See RDF schemas for other schemas.

Use in HTML metadata
To use Dublin Core for HTML metadata, only these specifications are relevant:
 * The Dublin Core Metadata Element Set, as formally defined at http://purl.org/dc/elements/1.1/
 * Element Refinements, as formally defined (amongst others) at http://purl.org/dc/terms/

Note that the refinements, like created, are intended to be used with the base term. For example, dcterm:created is a refinement of dc:date, creating date.created. Such a refinement can be specified in these two, equivalent, ways:

 

See the HTML Metadata article for more information how to define meta-data in HTML documents.

You need to specify the URI of the formal definitions if you define the namespace. The human readable description can be found at http://dublincore.org/documents/dcmi-terms/.

Dublin Core Elements
The Dublin Core Element Set v1.1 defines:
 * contributor:The person, organisation, or service responsible for making contributions to the content of the resource
 * coverage:The extent or scope of the content of the resource, like geographic location, date range or jurisdiction.
 * creator:The person, organisation, or service primarily responsible for making the content of the resource.
 * date:A date associated with an event in the life cycle of the resource. Typically, the creation date.
 * description:An account of the content of the resource, like abstract, or table of contents.
 * format:The physical or digital manifestation of the resource. For electronic formats, recommended practice is to use a MIME type.
 * identifier:An unambiguous reference to the resource within a given context, like URL or URN. For example "urn:ISBN:8884530431"
 * language:A language of the intellectual content of the resource. Recommended practice is to derive a value from RFC 3066 and ISO 639 (e.g. "en" or "en-GB")
 * publisher:An entity responsible for making the resource available.
 * relation:A reference to a related resource.
 * rights:Information about rights held in and over the resource. This may include copyright, intellectual property rights, or license.
 * source:A reference to a resource from which the present resource is derived. See also the relation refinements.
 * subject:The topic of the content of the resource. Recommended is to specify multiple subject lines, each with a separate keyword.
 * title:A name given to the resource.
 * type:The nature or genre of the content of the resource. Recommended is to use the DCMI Type Vocabulary for values.

Dublin Core Terms
The Dublin Core Terms Namespace defines:
 * audience:A class of entity for whom the resource is intended or useful.
 * audience.educationLevel:A general statement describing the education or training context. Alternatively, a more specific statement of the location of the audience in terms of its progression through an education or training context.
 * coverage.spatial:Spatial (geographic location) characteristics of the content of the resource.
 * coverage.temporal:Date or time range related to the content of the resource.
 * date.available:Date (often a range) that the resource will become or is available.
 * date.created:Date of creation of the resource.
 * date.modified:Date on which the resource was changed.
 * date.dateCopyrighted:Date of a statement of copyright.
 * date.dateSubmitted:Date of submission of the resource (e.g. thesis, articles, etc.).
 * date.dateAccepted:Date of acceptance of the resource (e.g. of thesis by university department, of article by journal, etc.).
 * date.issued:Date of formal issuance (e.g., publication) of the resource.
 * date.valid:Date (often a range) of validity of a resource.
 * description.abstract: A summary of the content of the resource.
 * description.tableOfContents:A list of subunits of the content of the resource.
 * format.extend:The size or duration of the resource.
 * identifier.bibliographicCitation:A bibliographic reference for the resource. Recommended is to make this an extensive plain text field, and use identifier for URI, ISBN, etc.
 * provenance:A statement of any changes in ownership and custody of the resource since its creation that are significant for its authenticity, integrity and interpretation.
 * relation.conformsTo:A reference to an established standard to which the resource conforms.
 * relation.hasFormat:The described resource pre-existed the referenced resource, which is essentially the same intellectual content presented in another format.
 * relation.isFormatOf:The described resource is the same intellectual content of the referenced resource, but presented in another format. See also the standard alternative keyword.
 * relation.hasPart:The described resource includes the referenced resource either physically or logically.
 * relation.isPartOf:The described resource is a physical or logical part of the referenced resource.
 * relation.hasVersion:The described resource has a version, edition, or adaptation, namely, the referenced resource.
 * relation.isVersionOf:The described resource is a version, edition, or adaptation of the referenced resource.
 * relation.references:The described resource references, cites, or otherwise points to the referenced resource.
 * relation.isReferencedBy:The described resource is referenced, cited, or otherwise pointed to by the referenced resource.
 * relation.replaces:The described resource supplants, displaces, or supersedes the referenced resource.
 * relation.isReplacedBy:The described resource is supplanted, displaced, or superseded by the referenced resource.
 * relation.requires:The described resource requires the referenced resource to support its function, delivery, or coherence of content.
 * relation.isRequiredBy:The described resource is required by the referenced resource, either physically or logically.
 * rights.accessRights:Information about who can access the resource or an indication of its security status.
 * rights.license:A legal document giving official permission to do something with the resource. Recommended best practice is to identify the license using a URI.
 * rightsHolder:A person or organization owning or managing rights over the resource.
 * title.alternative:Any form of the title used as a substitute or alternative to the formal title of the resource, including abbreviations and translations.

In addition, the terms namespace defines accrualMethod, accrualPeriodicity, accrualPolicy, audience, instructionalMethod, audience.mediator, and format.medium. These terms do not seem very useful to me.