Ontology is a formal specification of knowledge by a set of concepts with in a domain and their semantic relationship. Different Ontologies are devolved by developer for a same domain differently. Furthermore, ontology tools using different language. Ontology merging in semantic web is used to resolve the heterogeneity problem among the source ontology. The language level and ontology level mismatches are the heterogeneity problem in the ontology merging. Lexical matching strategies resolve the syntax based on Jaro distance. The word net is a lexical database with synset which solve the problem of semantic mismatches. A knowledge base is constructed by using Semantic Web Rule Language (SWRL) for ontology level mismatches. A merging framework identifies the similarities and dissimilarities of source ontologies are merged to resolve the heterogeneity problem. Keywords: Ontology, Heterogeneity problem, word net, Lexical, Semantic, SWRL