Synopsis In order to keep pace with the continuing the rapid developments and expanding vocabularies in all areas of environmental science and engineering, an attempt has been made in this unique and updated dictionary, to encompass terms that are frequently used in connection with different aspects of environment viz, air, water, soil, ecology, noise, solid waste, EIA, wild life, environmental legislation. The content and the style of presentation of dictionary is evident from the comprehensiveness of its coverage, simplicity and contextual relevance of the explanations wherever necessary. Throughout the process of compilation and editing, the sincere effort was to make it to serve as a valuable reference tool for environmental engineers, scientists, technologists, consultants as well as the students of multi-disciplinary fields of environmental science and engineering.