Updated quarterly, The Oxford English Dictionary is the accepted authority on the evolution of the English language over the last millennium. It is an unsurpassed guide to the meaning, history, and pronunciation of over half a million words, both present and past. It traces the usage of words through 2.5 million quotations from a wide range of international English language sources, from classic literature and specialist periodicals to film scripts and cookery books. The OED covers words from across the English-speaking world, from North America to South Africa, from Australia and New Zealand to the Caribbean. It also offers the best in etymological analysis and in listing of variant spellings, and it shows pronunciation using the International Phonetic Alphabet.
Oxford English Dictionary
The OED Online contains the complete text of the 20-volume Second Edition, first published in 1989, together with its 3-volume Additions Series, published in 1993 (volumes 1 and 2) and 1997 (volume 3).