Attorney
a person appointed to do something for and in the stead and name of another. An attorney may have general powers to act for another; or, his power may be special, and limited to a particular act or acts. A special attorney is appointed by a deed called a power or letter of attorney, specifying the acts which he is authorized to do.
An attorney at law is a person qualified to appear for another before a court of law to prosecute or defend any action on behalf of his client. The rules and qualifications, whereby one is authorized to practice as an attorney in any court are very different in different countries, and in the different courts of the same country.