Attempts by the US Air Force, Human Factors and Ergonomics Society, and Board of Certification in Professional Ergonomics in the US, the Harmonization of European Training Programs for the Ergonomics Profession project group in Europe, and the International Ergonomics Association to determine the scope of ergonomics and its technology are reviewed. Based on these data, and the author's own observations of ergonomics internationally, the technology of ergonomics is defined as human-system interface technology (HSIT). HSIT is proposed to have five identifiable components. Each of these components is described, including a brief history of its development. Because it has developed a unique technology, the author concludes that ergonomics has evolved into a unique, stand-alone discipline that can be defined most directly by its technology. Further, that educating the general public about HSIT will increase public understanding of the nature and scope of ergonomics and its potential for enhancing organizational performance and the quality of human life.