The scientific and technical terms can best be understood in context of their definitions. Thus, the Commission prepares definitional dictionaries in all subjects/fields. Generally, a glossary contains the technical terms of English along with their Hindi or Regional language equivalents whereas, a definitional dictionary conceptually explains the technical terms of English along with their Hindi or Regional languages equivalents in few sentences. Thus definitional dictionaries are more important and useful for the students, teacher, researchers, scholars, scientists and other users. In fact, a definitional dictionary is an extension of the process of evolution of terminology for ensuring better understanding and usage of the term.