This second edition contains a collection of technical abbreviations, acronyms, and identifiers (in short 'terms') that are used in information and communication technologies and other related areas. They have become part of the 'normal' vocabulary in many industries, institutes, organizations and universi­ ties. Too often they are used without mentioning what they stand for. The main area covered by this dictionary is Information and Communication Technology (ICT). This includes computer and communication hardware and software, communication networks, the Internet and the World Wide Web, and automatic control. Other areas covered are ICT-related techniques,solutions, products, processes and activities. The dictionary also contains symbolic names of organizations and institu­ tions directly connected to the subjects listed above, as well as the abbreviated names of conferences, symposia, workshops where the mentioned subject areas are treated. In some cases the standard two-letter country codes are listed between parenthesis at the end of every explained term and the country where the term originated. This is a reference book that is important for all practitioners and users in the areas mentioned above. Technical publications often omit the meaning of terms and confront the reader with jargon too often difficult to understand. Readers can use this book as a complete reference guide without having to guess what the letters of the terms stand for. This new edition contains close to 35.000 terms. Approximately ten thousand new items have been added. Obsolete and less relevant terms have been deleted.