Dublin Core is the name of a metadata format defined on the basis of international consensus which has defined a minimal information resource description, generally for use in a WWW environment.
The "Deutsche Institut für Normung e.V." is a German organization with the goal to create rules for rationalization, quality assurance and security, pollution control and communications in business, technology, science, administration and the public. Like other standardization institutes, DIN is also a member of ISO.
The Domain Name System was introduced in 1984 as a hierarchy for ordering then names of network nodes. A so called Domain Name Server is used to translate the names to IP addresses, which are used by the network components to identify a target machine, and back.