The Oxford English Dictionary (OED) is widely regarded as the accepted authority on the English language. It is an unsurpassed guide to the meaning, history, and pronunciation of 600,000 words— past and present—from across the English-speaking world.
As a historical dictionary, the OED is very different from those of current English, in which the focus is on present-day meanings. You’ll still find these in the OED, but you’ll also find the history of individual words, and of the language—traced through 3 million quotations, from classic literature and specialist periodicals to films, scripts, and cookery books. The OED started life more than 150 years ago.