A person suspected of or charged with an offense goes to a court hearing in order to plead their case before a judge or jury. It is common for a person to be represented by a lawyer in order to provide him or her with a case and argue his or her plead on his or her behalf. This type of lawyer is a defense lawyer, and is typically a specialization for lawyers.
A defense lawyer usually acts as an advocate or legal counsel for a client in a court case. The attorney presents an argument on behalf of his or her client that provides the best feasible resolution under the terms and conditions set forth by the law. Some attorneys may specialize in an area of law such as corporate law, criminal law, or family law. Specializations make it easier for individuals to seek out attorneys to represent them based on the issue at hand. Thus, a defense lawyer may sub specialize in criminal defense law, civil defense law, and others. It is the duty of the defense lawyer to argue the defense of his or her client to the best of his or her abilities. It is not necessarily the job of a defense lawyer to prove the innocence of his or her client.
The term defense lawyer is derived from the client that the lawyer is protecting, the defendant. Most defense lawyers begin their career as state prosecutors, lawyers who represent victims referred by the state. Such lawyers act in the interest of the victim without necessarily arguing on behalf of them directly.