New industries, like the information technology industry, depend on the creation of new terminology to communicate the new concepts and products produced. In the case of building software products, terminology is particularly important because the terms are operational components of the product itself; therefore, effective and diligent terminology management is critical to the development and localization of software products. The paper describes the process of software localization, the parts of the software concerned, and the tools involved. It examines the terminology management practices in the software localization process, especially data modelling principles for terminology management systems.