Ontology engineering is a field of Computer Science that covers the methods and methodologies for building ontologies. The purpose of Semantic Web ontologies is to achieve a common and shared knowledge ready to be transmitted between applications, providing interoperability across organizations of different areas or different views of the same area. Ontology transformation is the development of a new ontology to deal with the new requirements of an existing ontology for a new purpose. Creating a new single coherent ontology from two or more ontologies of the same knowledge domain is known as ontology merging. Ontology integration is the creation of a new ontology from two or more source ontologies from different knowledge domains. Ontology mapping is a formal expression to define the semantic relationships between entities from different ontologies. Ontology alignment is the process of creating a consistent and coherent link between two or more ontologies where statements of the first ontology confirm the statements of the second ontology.