URNEditCreated 6/5/2007, updated 5/18/2017A URN or Uniform Resource Name is a special subclass of URI. For example, a book’s ISBN number can be written as a URN like urn:isbn:0451450523. See also Wikipedia article on URNs: http://en.wikipedia.org/wiki/Uniform_Resource_Name Related RFCs RFC 1737 ("Functional Requirements for Uniform Resource Names") RFC 2141 ("URN Syntax") RFC 3986 ("Uniform Resource Identifier (URI): Generic Syntax") wiki