This accessible and authoritative reference covers commonly encountered terms and concepts in physics and includes key terms from mathematics, astrophysics, metallurgy, electronics, and physical chemistry. This third edition includes 1,000 new entries, with coverage of areas such as particle physics, cosmology, and computer science, and up-to-date entries on topics such as Higgs field, anthropic principle, nanotubes, and nanotechnology. The entries are written in a clear and explanatory style to provide both straightforward definitions and invaluable background information. This approach, combined with an extensive cross-referencing system, enables the reader to place each entry in a broader scientific context. Line drawings are included whenever the meaning of a word can best be conveyed by means of diagram, and a range of tables of essential scientific information is provided. It is an essential reference for anyone interested in this important field of science.