The Longman Dictionary of Contemporary English (LDOCE), first published by Longman in 1978, is an advanced learner's dictionary, providing definitions using a restricted vocabulary, helping non-native English speakers understand meanings easily. It is available in four configurations:
The dictionary is currently in its sixth edition. The premium website was revised in 2014 and 2015. It now offers over a million corpus examples (exceeding the paper version's), and includes sound files for every word, 88,000 example sentences, and various tools for study, teaching, examinations and grammar. The 9000 Most Important English Words to Learn have been highlighted via the Longman Communication 9000.
The free online version was updated in 2008 and offers search (with spelling assistance), definitions, collocations, and many examples and illustrations.
A key feature of the LDOCE is its utilization of the Longman Defining Vocabulary, a 2000-word controlled defining vocabulary used to write all of the definitions in the dictionary. This defining vocabulary was developed from Michael West's General Service List of high-frequency words and their most common meanings.
The controlled defining vocabulary is not only helpful to second-language learners, but has also facilitated the use of the LDOCE as a machine-readable dictionary in computational linguistics research.
It is a version of LDOCE specialized for collocations, synonyms, antonyms, designed for intermediate to advanced level learners.