For the past 150 years public schools in the United States have, in one form or another, tried to address the presence of children in classrooms whose cognitive, behavioral or physical characteristics have been deemed sufficiently problematic to merit a "special" education. Current federal law identifies thirteen categories of "disability" that schools now use to provide such special education services in schools. This essay explores both the evolution and function of special education terminology, that is, language referring not only to categories of disability but also to depictions of children, conditions, practices, and especially attitudes that infuse special education and are fundamental to defining its form and character. While the terminology has undergone considerable evolution and change over these many years, the meanings and functions behind the words continue to evoke confusion, controversy, and a powerful need for critique and dialogue. This has become profoundly important in the world of public education, where formal and informal curricula and interpersonal relations among large numbers of diverse actors and agents have assumed immeasurable importance in the lives of children, families, teachers, and other parties who share a strong and vested interest in the nature of this work.