J.D. is the main professional law degree in the United States. People write it after a name — Maria Chen, J.D. — to show they finished law school. In the US you usually do a first university degree in any subject, then about three more years at a law school; the J.D. is that second piece, and it is what most people need before they can sit the exam to become a lawyer. The letters stand for Juris Doctor, also called Doctor of Jurisprudence: Latin for a high degree in law. Though actually, the “Doctor” is a university title, not a medical one. People with a J.D. are not physicians, and in ordinary American life they are almost never called “Doctor”; that word is kept for medical doctors and, sometimes, for people with a research Ph.D. The J.D. is formal. You see it on business cards, email signatures, court papers, and university staff lists, not in casual chat. Other countries often train lawyers with an undergraduate law degree (an LL.B.) instead; the work is similar, the school path is not.