The Juris Doctor (abbreviated J.D.) is the degree awarded in the US (and some common law countries) after the completion of law school (typically a three-year post-undergraduate program, which does not require a thesis). This is the replacement of the Bachelor of Law (See Bachelor of Law). Most states requires a J.D. to be admitted to the bar (and thus to practice law).
The degree awarded in the US for the completion of law school. Most American law schools have a three year curriculum.