The
Oxford English Dictionary (OED) is a comprehensive multi-volume
dictionary published by the
Oxford University Press. Generally regarded as the definitive dictionary of
Modern English, it defines around 500,000
headwords and includes some 2.5 million illustrative
quotations.
Although the OED is a British institution, and perhaps most comprehensive with regard to
British English, its policy is to attempt to record all known uses and variants of a word in
all varieties of English, worldwide, past and present. To quote 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 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.
The OED is the starting point for virtually all scholarly work regarding words in English.