  This Ontologies are widely used as a means for solving the information
heterogeneity problems on the web because of their capability to provide
explicit meaning to the information. They become an efficient tool for
knowledge representation in a structured manner. There is always more than one
ontology for the same domain. Furthermore, there is no standard method for
building ontologies, and there are many ontology building tools using different
ontology languages. Because of these reasons, interoperability between the
ontologies is very low. Current ontology tools mostly use functions to build,
edit and inference the ontology. Methods for merging heterogeneous domain
ontologies are not included in most tools. This paper presents ontology merging
methodology for building a single global ontology from heterogeneous eXtensible
Markup Language (XML) data sources to capture and maintain all the knowledge
which XML data sources can contain
