A model for describing the world that consists of a set
of types, properties, and relationship types. Ontologies in
computer science came out of artificial intelligence, and
have generally been closely associated with logical
inferencing and similar techniques, but have recently begun
to be applied to information retrieval.
Topic maps
A subject-based classification technique. Topic maps are
organized around topics, and each topic is used to represent
some real-world thing. In topic maps, three constructs are
provided for describing the subjects represented by the
topics: names, occurrences, and associations.
