The present dictionary is an effort to inform the readers about the various terms and concepts that constitute the field of knowledge of chemistry. The genesis of chemistry can be traced to ancient times to the widely observed phenomenon of burning that led to metallurgy-the art and science of processing ores to get metals; and today, in an era defined by scientific progress and technology, the chemical industry, with its wide applications in a number of fields, represents an important economic activity with billions in turnover revenues. The dictionary is aimed at not just acquainting the readers with the foundational basics of chemistry, but make them aware of how chemistry has made inroads into various arenas of human life. It is hoped that the dictionary proves to be resourceful for all.