The Oxford English Dictionary (OED)
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 book.
Click on The Oxford English Dictionary (OED) to open the resource.