Most types of dictionary are available in electronic form. These include general-purpose monolingual and bilingual dictionaries, historical dictionaries such as the Oxford English Dictionary, monolingual learner’s dictionaries, and specialized dictionaries of every type,such as medical or legal dictionaries,thesauruses, travel dictionaries, dictionaries of idioms, and pronunciation guides.
Most of the early electronic dictionaries were, in effect, print dictionaries made available in digital form: the content was identical, but the electronic editions provided users with more
powerful search functions. But soon the opportunities offered by digital media began to be exploited. Two obvious advantages are that limitations of space (and the need to optimize its use) become less pressing, so additional content can be provided; and the possibility arises of including multimedia content, such as audio pronunciations and video clips.
Electronic dictionary databases, especially those included with software dictionaries are often extensive and can contain up to 500,000 headwords and definitions, verb conjugation tables, and a grammar reference section. Bilingual electronic dictionaries and monolingual dictionaries of inflected languages often include an interactive verb conjugator, and are capable of word stemming and lemmatization.