This edition of the Dictionary, published eighteen years after its first appearance, is an enlarged and improved version of the original corpus. During the past two decades, the Dictionary has achieved widespread acceptance and use. In the interim, modern written Arabic has continued to exhibit vigorous lexical growth. Therefore, feeling the need to fill in many gaps and update the corpus, the author again undertook systematic collection of material. In addition to many neologisms of recent origin, the author has incorporated much older material attested in present-day contexts, which had not yet appeared in the Dictionary, as well as numerous improvements and corrections. The result is that this revised edition has nearly 200 new pages.