DICTIONARY

Dictionary is a book or collection of alphabetically listed words in a specific language, with definitions, etymologies, pronunciations, and other information; or a book of alphabetically listed words in one language with their equivalents in another, also known as a lexicon. According to Nielsen a dictionary may be regarded as a lexicographical product that is characterised by three significant features: (a) it has been prepared for one or more functions; (b) it contains data that have been selected for the purpose of fulfilling those functions; and (c) its lexicographic structures link and establish relationships between the data so that they can meet the needs of users and fulfil the functions of the dictionary.

In many languages, words can appear in many different forms, but only the undeclined or unconjugated form appears as the headword in most dictionaries. Dictionaries are most commonly found in the form of a book, but some newer dictionaries, like StarDict and the New Oxford American Dictionary are dictionary software running on PDAs or computers. There are also many online dictionaries accessible via the Internet.

The first purely English alphabetical dictionary was A Table Alphabeticall, written by English schoolteacher Robert Cawdrey. The only surviving copy is found at the Bodleian Library in Oxford. Yet this early effort, as well as the many imitators which followed it, was seen as unreliable and nowhere near definitive.

Science Dictionaries have existed from the 6th century BCE when the Chinese started organizing all of their scientifically important knowledge, and combining them into scrolls. The amount and type of information ranged from theories, species, experiments, essays, research, and various other forms of knowledge.