A more thorough explanation:

An attorney at law, also known as an attorney-at-law, is a legal professional who is licensed to practice law and represent clients in legal matters. The term is often used interchangeably with lawyer.

For example, in the case of Supreme Court of Virginia v. Consumers Union of U.S., Inc., the term attorney at law is used to refer to the lawyers who represented the parties in the case.

Attorneys at law have a duty of confidentiality to their clients, meaning they must keep any information shared by their clients confidential. They are also bound by the attorney-client privilege, which protects communications between attorneys and their clients from being disclosed in court.

Another type of attorney is an attorney-in-fact, who is authorized to act on behalf of another person in legal or business matters. An attorney of record is the attorney who is officially listed as representing a party in a legal case.