This manual provides definitions of terms related to developmental disabilities and special education. The first section focuses on categorical areas of impairment, defining concepts such as educable mentally impaired, trainable mentally impaired, severely mentally impaired, severely multiply impaired, hearing impaired, visually impaired, physically and otherwise health impaired, speech and language impaired, emotionally impaired, and learning disabled. The next sections contain definitions of commonly used special education terms; and explanations of professional jargon and cryptic statements, including terms commonly used in connection with emotional, hearing, mental, physical, and visual impairments and learning disabilities. Subsequent sections explain common and clinical abbreviations and symbols; provide the names and addresses of relevant associations, organizations, and Michigan-based parent advocacy groups; list parent awareness program books; and cite reference books, journals, and audiovisuals dealing with particular disabilities. A bibliography is included. (LAL)