The availability and the proliferation of ontologies are crucial for the success of the Semantic Web. As consequence, a great number of researchers are working on method and techniques to build ontologies through automatic or semi-automatic processes, which perform knowledge acquisition from texts, dictionaries and structured and semi-structured information sources. On the other hand, reverse engineering, when applied to software engineering, uses a collection of theories, methodologies and techniques to support information abstraction and extraction from a piece of software. In this paper we present a semi-automatic reverse engineering approach to acquire OWL ontology corresponding to the content of relational database. Our approach is based on the idea that the semantics extracted by analyzing HTML forms will be used to restructure and enrich the relational schema. OWL ontology is constructed through a set of transformation rules from the enriched schema. The main reason for this construction is to make the relational database information that is available on the Web machine-processable and reduce the time consuming task of ontology creation.