The Concise Oxford English Dictionary is one of the best-known of the 'smaller' Oxford dictionaries. The latest edition contains over 240,000 entries and 1,728 pages. Its 12th edition, published in 2011, is used by both the United Nations (UN) and NATO as the current authority for spellings in documents in English for international use. It is available as an e-book for a variety of handheld device platforms. In addition to providing information for general use, it documents local variations such as United States and United Kingdom usage.

A dictionary is a listing of lexemes from the lexicon of one or more specific languages, often arranged alphabetically, which may include information on definitions, usage, etymologies, pronunciations, translation, etc. It is a lexicographical reference that shows inter-relationships among the data.