This book is the Dictionary of Computer Science and Engineering which contains around 1500 computer terminologies. The aim of this book is to impart to students the knowledge and skills that are needed to successfully face the viva voice exams and interviews. Here each terminology is well defined and explained clearly. In this book the words are arranged in alphabetical order which helps to search the words very quickly, this book covers the most commonly and frequently used terminologies from the entire subjects related to Computer Science, Applications, and Engineering and Technology streams. This book is useful for all streams of students who need to learn and know about the meaning, definition and explanatory of most frequently using terminologies in the field of Information Technology. These words are most frequently used and asked has questions during the examinations, practical viva-voice exams and campus interview. This book is most useful for all Diploma, Under Graduate and Post Graduates students who are studying or completed the B.E, MCA, M.Sc in Computer Science, BCA, Diploma in Computer Science and Engineering, MS in computer science, B.Sc in Computer science and Computer Maintenance. This book can also be referred for research scholars’ and professionals for their mastering in the computer terminologies.