Blacks's Law Dictionary 10ed.

For more than a century, Black's Law Dictionary has been the gold standard for the language of law. Today, it's the most widely cited law book in the world. By Editor in Chief Bryan A. Garner, the world's leading legal lexicographer, the 10th Edition is the most authoritative, comprehensive law dictionary ever published. It contains more than 50,000 terms and includes:

More than 7,500 terms new to this edition, including affluenza defense, bioweapon, cryptanalysis, gazump, hacker, legaldygook, intrapreneur, mommy track, one-bite rule, psephology, unperson, and zero-tolerance law
16,000 new definitions and expanded bibliographic coverage, with more than twice as many sources quoted and cited than in the 9th Edition
Earliest usage dates in English-language contexts for nearly all terms (Black's is the only legal dictionary with this feature)
Trusted authority – every term has been reviewed for accuracy by attorneys across the country
Definitions of more than 1,000 law-related abbreviations and acronyms
Pronunciation guidance
Thoroughly reviewed and edited Latin maxims, with 900 new maxims added