Basic MCF Vocabulary

Here is some basic vocabulary for describing content. Though it is certainly possible for anyone to invent their own vocabulary, it would be be highly preferred if we can all use the same terms to refer to the same things. The MCF definitions of the units described on this page will soon be found here.


As a convention, Categories (aka sets, types, classes) are in the singular. So, the category of all people is called Person and of all organizations is called Organization.

Also, as a convention, categories start with a capital letter.

The identifier and names of these categories are the same.
  1. SubjectCategory
    The category of subjects. An example is the Arts category in Yahoo! (whose idenitifer is
  2. SubjectCategorization
    Categorizations such as Yahoo! or Excite. Note that Yahoo! itself is not a SubjectCategory but a SubjectCategorizationCategory. The relation between Yahoo! (Yahoo.mcf) and Yahoo! Arts is the relation categorizationType.
  3. Content
    Examples include this web page or the home page for Apple Computer. Subtypes include Web Pages, Databases, etc.
  4. Organization
    Examples include Apple Computer, United States and the Peace Corps. Organizations are mutually disjoint with people.
    Coming soon : a list of kinds of organizations.
  5. Person
    The category of people.
  6. AgentCategory
    A supertype of both PersonCategory and OrganizationCategory.
  7. NaturalLanguage
    Examples include English, French, etc. Coming soon : a more complete list of content categories.
  8. ContentGenre
    subtypes include Poem, PersonalHomePage, CorporateHomePage, Thesis. Note that each of these is a category.
    Coming soon : a more complete list of content categories.
  9. TableOfContents
    Examples include the table of contents of a book or of a website (such as ProjectX/FullApple.mcf).


As a convention, predicates start with a lower case letter. The identifier and names of all predicates are the same.
  1. authorIndividual
    The individual person(s) who is(are) the authors of the content object. The entries are not names of the authors but references to objects corresponding to the authors. The name, email address, etc. of the author can be specified on this object.
  2. authorOrganization
    The organization which is the author of the content object. For example, Apple Computer is the authorOrganization of this page.
  3. author
    The generalization of the previous 2 slots. The is a genlSlot of both of them.
  4. name
    The name of a thing. Names are represented using strings. Pretty much anything, subject categories, people, organizations, content objects, etc. can have a name.
  5. emailAddress
    A string representing the email address of an agent.
  6. homePage
    The url of the home page(s) of an agent.
  7. size
    The size of a content object in bytes. Represented using an integer.
  8. loadSize
    The total number of bytes, including inline images, plugins, etc. of a content object.
  9. firstPublicationDate
    The date on which a content object was first published. Dates are represented using strings. Dates follow the month-day-year model, though the interface may present this anyhow. We will soon have some scheme for allowing different syntaxes for dates.
  10. lastRevisionDate
    The date on which the content object was last modified.
  11. validUntilDate
    The date until the information in this content object is valid.
  12. versionNumber
    The version number of this content object or subject category. A string.
  13. description
    A natural language string describing the object.
  14. subject
    The subject categories that this content object falls under. parent is a genlSlot of subject.
  15. publisher
    The organization that is the publisher of the content object.
  16. editor
    The person or organization that is the editor of the content object.
  17. language
    The language (typically a natural language such as English or French) in which the content is primarily encoded.
  18. toc
    One or more tables of contents of which this content object is a part.
  19. tocOf
    This slot is the inverse of toc. It typically appears in headers of mcf files that are the tables of contents of web sites.
  20. siteHomePage
    The home page for the site of which this content object is a part.
  21. helpPage
    The page at which help can be found regarding this content object.
  22. mirrors
    Mirror urls for this content object. Urls are just strings and need not be preceeded with # symbols.
  23. contentGenre
    The kind of content that is this content object (poem, personal home page, etc.) Of course, a content object can be both a poem and a personal home page (though more likely, the home page includesContent a poem.)
  24. linksTo
    The content objects that a content object has hyperlinks to. parent is a genlSlot of linksTo.
  25. includesContent
    To be used when one content object includes another (such as an HTML page including an image or a poem).
  26. categorizationType
    The relation between a subjectCategory (such as Yahoo! Arts) and the categorization family it belongs to (such as Yahoo!).
  27. subTopic
    A relational between two subject categories such as Yahoo Arts and Yahoo Arts Museums which states that the later is a more specific subject category of the former.
  28. objectIcon
    An icon that can be used to represent the object. The value is typically the object corresponding to a GIF or JPEG, but could also be a platform specific encoding. Preferably, it will be one object with several different encodings being available.