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A counsel or a counsellor gives advice, more particularly in legal matters.
The legal system in England uses the term counsel as a synonym for a barrister-at-law, and may apply it to mean either a single person who pleads a cause, or collectively, the body of barristers engaged in a case.
The legal term counsellor, or, more fully, counsellor-at-law, became practically obsolete in England, but continued in use locally in Ireland as an equivalent to barrister, where a Senior Counsel (S.C.) is equivalent to the English QC or KC.
In the United States of America, the term counselor-at-law designates, specifically, an attorney admitted to practice in all courts of law; but as the United States legal system makes no formal division of the legal profession into two classes, as in England, most US citizens use the term loosely in the same sense as lawyer, meaning one who versed in (or practising) law.
In the United States and Canada, many large and midsize law firms have lawyers with the job title of "counsel", "special counsel" or "of counsel." These lawyers are employees of the firm like associates, although some firms have an independent contractor relationship with them. But unlike associates, and more like partners, they generally have their own clients, manage their own files, and supervise associates. For more information, see the Law firm article.