Oxford English Dictionary
The definitive record of the English language, the OED is the accepted authority on the evolution of the language. It traces the use of more than 600,000 words over the last 1,000 years through 3 million quotations. It defines and illustrates how long a word has been used, where it came from, when it first entered the language, and how its meaning has changed over time and around the world. Quotations come from modern and historical texts, from classic literature and specialist periodicals, film scripts, wills, cookery books, and blogs.