The basic problem in WSD is the mapping from term-space (i.e. documents) to conceptspace
(i.e. knowledge models). Ontologies are one form of knowledge model that
formally represent a universe of discourse by describing the relationships between its
concepts (Gruber, 1993). Enriching documents with machine understandable mark-up
(i.e. metadata) is one knowledge-based approach. The aim of extending documents with
metadata is, among others, to remove ambiguities in the documents.