The Oxford English Dictionary is a historical dictionary of English, covering the language from the earliest times to the present day. It aims not only to show the current meanings of words, but also to trace their development through time. Entries contain detailed etymological analysis and are illustrated by quotations from a wide range of English language sources from around the world, making the OED a unique historical record.

OED Online contains:

• the complete text of the OED's twenty-volume Second Edition and three-volume Additions Series
• draft material from the current OED project, representing the latest progress towards a completely revised and updated Third Edition - at present, this consists of entries in the range M to mamzer, with more entries added quarterly.