This dictionary consists of text and tables, covering all of the areas that are fundamental to understanding our physical world, and life within it. Included are physics - classical, relativistic, quantum, particle, and high-energy; chemistry - inorganic, organic, and physical; the geological sciences - geology, geophysics, oceanography, meteorology, palaeontology, and related areas of molecular, genetic, and evolutionary biology; and cosmology - including astronomy, astrophysics, and the genesis and evolution of the universe.The text features not only definitions but also explanations, formulas, and data. Entries best presented in tabular form are found in 70 tables that follow the text. The 5,000 definitions are both concise and rigorous, abbreviations are spelled out, and unfamiliar terms are themselves defined.