XML Topic Maps (XTM)
This specification provides a model and a grammar for representing the structure of information resources used to define topics, and the associations
(relationships) between topics. Names, resources, and relationships are said to be characteristics of abstract subjects, which are called topics.
Topics have their characteristics within scopes: i.e. the limited contexts within which the names and resources are regarded as their name, resource, and relationship characteristics.
One or more interrelated documents employing this grammar is called a topic map.
TopicMaps.Org is an independent consortium of parties developing the applicability of the topic map paradigm
[ISO13250] to the World Wide Web by leveraging the XML family of specifications.