Oxford English Dictionary This link opens in a new windowThe Oxford English Dictionary (OED) is widely regarded as the accepted authority on the English language. It is guide to the meaning, history, and usage of 500,000 words and phrases past and present, from across the English-speaking world. In addition to present-day word meanings, the OED also provides the history of individual words, sometimes from as far back as the 11th century, and of the language—traced through 3.5 million quotations, from classic literature and specialist periodicals to film scripts, song lyrics, and social media posts. Revised and updated regularly.