Dictionary of Physics has been compiled to meet the needs of students of Physics at all levels. It has been difficult to decide the limits of Physics as a subject. The terms and definitions have been frequently presented in brief or functional phrases, thus avoiding the more comprehensive type or treatment appropriate to larger reference works. An attempt has also been made to write the entries in a clear and lucid style to provide both straight forward definitions and invaluable background informations, clear and easy illustrations have been included wherever the meaning of a word can be best understood. The dictionary will be of immense value to the students of Physics and Engineerings and others studying or working in the related fields. This dictionary could be considered as a commendable achievement by any standards. Though the author has taken special care to cover all important and basic terms, yet he is fully aware about his limitations. The selection of the terms is a problem in such a project and it has been the aim of the author to strike a good balance.