School of Information Management & Systems. Spring 2003.
245 Organization of Information in Collections. Michael Buckland.

Dublin Core Metadata Initiative
http://dublincore.org/   Currently 16 Elements, some with recommended "Refinements". This is condensed from DCMI Elements and Element Refinements - a current list (2002-10-6) http://dublincore.org/usage/terms/dc/current-elements/

Element: Title. Definition: A name given to the resource. Refinement: Alternative title.
Element: Creator. Def: An entity primarily responsible for making the content of the resource. e.g. person, organisation, or service. Typically, use the name of a Creator.
Element: Subject [and Keywords]. Def: The topic of the content of the resource. Typically, expressed as keywords, key phrases or classification codes. Rec: Use a controlled vocabulary or formal classification scheme.
Element: Description. Def: An account of the content of the resource. e.g. abstract, table of contents, reference to a representation of content or a free-text account. Refinements: Table Of Contents; Abstract.
Element: Publisher. Def: An entity responsible for making the resource available. e.g. person, organisation, or service.
Element: Contributor. Def: An entity responsible for making contributions to the content of the resource. e.g. person, organisation, or service.
Element: Date. Def: A date associated with an event in the life cycle of the resource. Typically, date of creation or availability. Rec: YYYY-MM-DD and ISO 8601 [W3CDTF]. Refinements: [Date of] Creation; [Date(s) when] Valid; [Date(s) when] Available; [Date formally] Issued; [Date] Modified; Date Accepted [e.g as thesis, for publication]; Date Copyrighted; Date Submitted.
Element: Type. Name: Resource Type; Def: The nature or genre of the content of the resource. Incl. general categories, functions, genres, or aggregation levels for content. Rec: Use a controlled vocabulary (e.g. DCMI Type Vocabulary). Use FORMAT element for physical type.
Element: Format. Def: The physical or digital manifestation of the resource. e.g. media-type or dimensions (e.g. size and duration). Rec: Use controlled vocabulary (e.g. the list of Internet Media Types [MIME] defining computer media formats). Refinements: Extent [Size / duration]; Medium [Material or physical carrier of the resource].
Element: Identifier. Name: Resource Identifier. Def: An unambiguous reference to the resource within a given context. e.g. Uniform Resource Identifier (URI) (incl.URL; Digital Object Identifier (DOI); International Standard Book Number (ISBN).
Element: Source. Def: A Reference to a resource from which the present resource is derived. Rec. refer to a formal identification system.
Element: Language. Def: A language of the intellectual content of the resource. Rec. RFC 1766 a 2 or 3 letter Language Code (ISO 639) with optionally a 2-letter Country Code (from ISO 3166). e.g. 'en' for English, 'en-GB' for English used in the United Kingdom.
Element: Relation. Def: A reference to a related resource. Rec. a formal system. Refinements: "Is Version Of"; "Has Version"; "Is Replaced By"; "Replaces"; "Is Required By"; "Requires"; "Is Part Of"; "Has Part"; "Is Referenced By"; "References [other resource]"; "Is [same content but different] Format Of"; "Has Format" [same content as pre-existing resource in another format]; Conforms To [some standard].
Element: Coverage. Def: The extent or scope of the content of the resource. e.g. spatial location (a place name, geographic coordinates), temporal period (a period label, date, or date range) or jurisdiction (a named administrative entity). Rec: Thesaurus of Geographic Names [TGN]) and named places or time periods rather than numeric identifiers. Refinements: Spatial [characteristics of the intellectual content]; Temporal [characteristics of the intellectual content].
Element: Rights. Name: Rights Management. Def: Information about rights held in and over the resource. e.g. a rights management statement or a service.
Element: Audience: Def: For whom the resource is intended or useful. Refinements: Mediator [of access]; Audience Education Level.