The Oxford English Dictionary I.

The Oxford English Dictionary (OED), published by the Oxford University Press, is a descriptive (as opposed to prescriptive) dictionary[1] of the English language. As well as describing English usage in its many variations throughout the world, it traces the historical development of the language, providing a comprehensive resource to scholars and academic researchers.The second edition, published in 1989, came to 21,728 pages in 20 volumes.