According to the publishers, it would take a single person 120 years to type the 59 million words of the OED second edition, 60 years to proofread it, and 540 megabytes to store it electronically. As of 30 November 2005, the Oxford English Dictionary contained approximately 301,100 main entries. Supplementing the entry headwords, there are 157,000 bold-type combinations and derivatives; 169,000 italicized-bold phrases and combinations; 616,500 word-forms in total, including 137,000 pronunciations; 249,300 etymologies; 577,000 cross-references; and 2,412,400 usage quotations. The dictionary's latest, complete print edition (Second Edition, 1989) was printed in 20 volumes, comprising 291,500 entries in 21,730 pages. The longest entry in the OED2 was for the verb set, which required 60,000 words to describe some 430 senses. As entries began to be revised for the OED3 in sequence starting from M, the longest entry became make in 2000, then put in 2007.
Despite its impressive size, the OED is neither the world's largest nor earliest dictionary. The Dutch dictionary Woordenboek der Nederlandsche Taal, which has similar aims to the OED, is the largest and it took twice as long to complete. The earliest large dictionary is the Grimm brothers' dictionary of the German language, begun in 1838 and completed in 1961. The first edition of the Vocabolario degli Accademici della Crusca, which is the first great dictionary devoted to a modern European language (Italian), was published in 1612; the first edition of Dictionnaire de l'Académie française dates from 1694. The first edition of the official dictionary of Spanish, the Diccionario de la lengua española (produced, edited, and published by the Real Academia Española) was published in 1780. The Kangxi dictionary of Chinese was published even earlier, in 1716.
The OED's official policy is to attempt to record a word's most-known usages and variants in all varieties of English past and present, worldwide. Per the 1933 "Preface":
The aim of this Dictionary is to present in alphabetical series the words that have formed the English vocabulary from the time of the earliest records [ca. AD740] down to the present day, with all the relevant facts concerning their form, sense-history, pronunciation, and etymology. It embraces not only the standard language of literature and conversation, whether current at the moment, or obsolete, or archaic, but also the main technical vocabulary, and a large measure of dialectal usage and slang. It continues:
Hence we exclude all words that had become obsolete by 1150 [the end of the Old English era] ... Dialectal words and forms which occur since 1500 are not admitted, except when they continue the history of the word or sense once in general use, illustrate the history of a word, or have themselves a certain literary currency. The OED is the focus of much scholarly work about English words. Its headword variant spellings order list influences written English in English-speaking countries.
At first, the dictionary was unconnected to Oxford University but was the idea of a small group of intellectuals in London; it originally was a Philological Society project conceived in London by Richard Chenevix Trench, Herbert Coleridge, and Frederick Furnivall, who were dissatisfied with the current English dictionaries. In June 1857, they formed an "Unregistered Words Committee" to search for unlisted and undefined words lacking in current dictionaries. In November, Trench's report was not a list of unregistered words; instead, it was the study On Some Deficiencies in our English Dictionaries, which identified seven distinct shortcomings in contemporary dictionaries:
Incomplete coverage of obsolete words
Inconsistent coverage of families of related words
Incorrect dates for earliest use of words
History of obsolete senses of words often omitted