This comprehensive dictionary provides clear, concise definitions of terms from chemistry, physics, the geological sciences, and astronomy. The breadth of coverage and the accuracy of the entries are unsurpassed. Symbols and abbreviations are spelled out, and any unfamiliar terms used inmaking the definitions are themselves defined in the dictionary. The author has included quantitative information wherever pertinent, and has added a number of tables in the appendix to provide additional data. The most comprehensive dictionary available in the physical sciences, this readable,convenient reference will be essential for students and researchers in earth sciences, physics, chemistry and astronomy, as well as for educated lay readers with an interest in science.