General dictionaries are used for reference and academic purposes! Until now I’ve never paid attention to any other type. But, as a result of someones curiosity, I have come to learn that there are several dictionary types as well. There are linguistic, encyclopedic and historic and etymological dictionaries. Special dictionaries that tell of dialect, technical terms, glossaries and slangs, jargon and argot. Homonyms and synonyms and acronyms as well as antonyms. There are lots of different types of dictionaries and more descriptions can be found by searching at ‘An Introduction to Lexicography, Types of Dictionaries’.