What is Attorney At Law?

Legal Definition
Attorney at law or attorney-at-law, usually abbreviated in everyday speech to attorney, is the preferred term for a practising lawyer in certain jurisdictions, including South Africa (for certain lawyers), Sri Lanka, and the United States. In Canada, it is used only in Quebec. The term has its roots in the verb to attorn, meaning to transfer one's rights and obligations to another.
-- Wikipedia
Legal Definition
Someone authorized to practice law; a lawyer. Also called attorney and public attorney.
Illustrative caselaw
See, e.g. Supreme Court of Virginia v. Consumers Union of U.S., Inc., 446 U.S. 719 (1980).
See also
Legal Definition
A party qualified to practice law in their jurisdiction. AKA attorney. Refer to advocate, barrister, counsel, lawyer, and queen's counsel.
Legal Definition
An advocate, counsel, official agent employed in preparing, managing, and trying cases in the courts. An officer in a court of justice, who is employed by a party in a cause to manage the same for him.

In English law. An attorney at law was a public officer belonging to the superior courts of common law at Westminster, who conducted legal proceedings on behalf of others, called his clients, by whom he was retained ; he answered to the solicitor in the courts of chancery, and the proctor of the admiralty, ecclesiastical, probate, and divorce courts. An attorney was almost invariably also a solicitor. It is now provided by the judicature act, 1873, § 87, that solicitors, attorneys, or proctors of, or by law empowered to practise in, any court the jurisdiction, of which is by that act transferred to the high court of justice or the court of appeal, shall be called "solicitors of the supreme court." Wharton.

The term is in use in America, and in most of the states includes "barrister," "counsellor," and "solicitor," in the sense in which those terms are used in England. In some states, as well as in the United States supreme court, "attorney" and "counsellor" are distinguishable, the former term being applied to the younger members of the bar, and to those who carry on the practice and formal parts of the suit, while "counsellor" is the advisee, or special counsel retained to try the cause. In some jurisdictions one must have been an attorney for a given time before he can be admitted to practise as a counsellor. Rap. & It.
-- Black's Law Dictionary
Legal Definition
A court officer authorized by those who employ him to represent them in litigation. See 3 Mich. 598.
-- Ballentine's Law Dictionary