The Oxford English Dictionary is the accepted authority on the evolution of the English language over the last millennium. It is a guide to the meaning, history, and pronunciation of over half a million words, both present and past.  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.