Black's Law Dictionary is the most widely used law dictionary in the United States. It was founded by Henry Campbell Black (1860–1927). It is the reference of choice for terms in legal briefs and court opinions and has been cited as a secondary legal authority in many U.S. Supreme Court cases.
The latest editions, including abridged and pocket versions, are useful starting points for the layman or student when faced with an unfamiliar legal term.
The first edition was published in 1891, and the second edition in 1910. The sixth and earlier editions of the book also provided case citations for the term cited, which some lawyers view as its most useful feature, providing a useful starting point with leading cases. The Internet made legal research easier than it ever had been, so many state- or circuit-specific case citations and outdated or overruled case citations were dropped from the seventh edition in 1999. The eighth edition introduced a unique system of perpetually updated case citations and cross-references to legal encyclopedias. The ninth edition was published in the summer of 2009.
Because many legal terms are derived from a Latin root word, the Dictionary gives a pronunciation guide for such terms. In addition, the applicable entries provide pronunciation transcriptions pursuant to those found among North American practitioners of law or medicine.
An online version of the eighth edition can be accessed through the paid Westlaw legal information service and as of late 2006, West Academic has published Black's Law Dictionary Digital, 8th edition (ISBN 9780314176103) which has toolbars that integrate with Microsoft Word, Mozilla Firefox and Internet Explorer. The second edition of Black's Law Dictionary (1910) is now in the public domain. The Lawbook Exchange, Ltd. has reprinted the first and second editions (ISBN 0-9630106-0-3 and ISBN 1-886363-10-2, respectively). Also, it is available as a Windows Phone application, and the tenth edition is available as an application for iOS devices.