Providing over 140,000 separate entries, this text collects together abbreviations, acronyms, contractions and symbols within astronomy, related space sciences and other related fields. Included are separate sections devoted to Greek letters, mathematical symbols and special signs and characters. Besides astronomy and space sciences, related fields such as: aeronautics; aeronomy; astronautics; atmospheric sciences; chemistry; communications; computer sciences; data processing; education; electronics; engineering; energetics; environmental; geodesy; geophysics; information handling; management; mathematics; meteorology; optics; physics; remote sensing and so on.