Topic Maps is a standard for the representation and interchange of knowledge, with an emphasis on the findability of information. The ISO standard is formally known as ISO/IEC 13250:2003.
To represent knowledge, topic map provide the following concepts:
Topic: A topic is the main concept of topic maps. A topic represents exactly one concept e.g. a person, place or point in time. A topic has one or more identifiers in form of URIs. If two topics in a topic map have at least one identifier in common, they are merged to make sure that a concept is only represented once in a map.
Occurrence: An occurrence represents one information resource of a topic. Occurrences are typed with other topics.
Association: An association connects topics. Each association is typed (with another topic). Each topic in an association plays a specific role, which is also typed with a topic representing the concept of the role.
The topic maps standard is more like a standard family. In addition to the topic maps model, standards for a contraint language (TMCL), Query Language (TMQL) and notations for Topic Maps (CTM, XTM) exist.
For more information: http://isotopicmaps.org
