The primary objective of this Glossary of Terms Used in Developmental and Reproductive Toxicology is to give clear definitions for those who contribute to studies relevant to these disciplines in toxicology, or must interpret them, but are not themselves reproductive physiologists or physicians. This applies especially to chemists who need to understand the literature of reproductive and teratogenic effects of substances without recourse to a multiplicity of other glossaries or dictionaries. The Glossary includes terms related to basic and clinical reproductive biology and teratogenesis, insofar as they are necessary for a self-contained document, and particularly terms related to diagnosing, measuring, and understanding effects of substances on the embryo, fetus, and the male and female reproductive systems. The glossary consists of about 1200 terms as primary alphabetical entries, and includes Annexes of common abbreviations, and examples of chemicals with known effects on human reproduction and development. The authors hope that among the groups who will find this glossary helpful, in addition to chemists, are toxicologists, pharmacologists, medical practitioners, risk assessors, and regulatory authorities. In particular, it should facilitate the worldwide use of chemical terminology in relation to occupational and environmental risk assessment.