J.D. is an abbreviation for the Latin "Juris Doctor", or Doctor of Law, and is the "law degree" typically awarded by an accredited U.S. law school after successfully completing three years of graduate law study. Generally, a 4-year undergraduate degree is required to be eligible for entry into a J.D. program. Prior to the practice of law, a J.D. holder is required to be member of the state bar association of the state in which he or she intends to practice. Admission to a state's bar requires that a J.D. holder either sit for the bar exam in that state, and submit to that state's procedures for verifying "character and fitness", or obtain admission administratively through reciprocity provisions providing that in some states, lawyers who have practiced in other states for a set period of time, may be admitted upon application.
Holders of a "Juris Doctor" often append the suffix Esq. to the end of their names, but are not commonly referred to as "Dr." While the "Juris Doctor", or Doctor of Law, is a Doctorate level professional degree, similar to the "Medicinæ Doctor" earned by Doctors of Medicine, the reasons why those holding a "Juris Doctor" degrees are not referred to as "Dr." have been lost to history.
The first year of a J.D. program is usually devoted to core courses on contracts, property law, torts and civil procedure. Later courses might include criminal procedure and criminal law, constitutional law, business entities and agency, commercial law, trusts and estates, family law, conflict of laws, rules of evidence, tax law, oil and gas law, environmental law, bankruptcy law, intellectual property law, labor law, jurisprudence, etc.