The present dictionary has been designed in order to serve the readers as a guide which would prove as a resourceful referral into understanding the World of science. A basic but thorough understanding of Scientific issues, development, discoveries and inventions is indispensable to the Education of a well-informed mind, and the dictionary is an endeavour in the process to attain just such a goal. Embarking on a process of informing readers the basic concept which inform the scientific field, this dictionary caters to readers of all ages, from 7 year-olds to right through 70. The main agenda behind the dictionary is to keep readers not just well-aware of Science in its various manifestations, but also to serve as a testimony to the power that science holds in our lives. It is hoped that the dictionary serves to be a resourceful guide for all.