Of counsel is often the title

Title

A title is a prefix or suffix added to someone's name to signify either veneration, an official position or a professional or academic qualification. In some languages, titles may even be inserted between a first and last name...

 of an attorney

Lawyer

A lawyer, according to Black's Law Dictionary, is "a person learned in the law; as an attorney, counsel or solicitor; a person who is practicing law." Law is the system of rules of conduct established by the sovereign government of a society to correct wrongs, maintain the stability of political...

 who is employed by a law firm

Law firm

A law firm is a business entity formed by one or more lawyers to engage in the practice of law. The primary service rendered by a law firm is to advise clients about their legal rights and responsibilities, and to represent clients in civil or criminal cases, business transactions, and other...

 or an organization, but is not an associate

Associate attorney

An associate attorney is a lower-level employee of a traditional law firm who does not hold an ownership interest as a partner.-Attorneys:An associate may be a junior or senior associate, but normally does not yet hold an ownership interest in the firm even if they have been associated with the...

 or a partner

Partner (business rank)

A partner in a law firm, accounting firm, consulting firm, or financial firm is a highly ranked position. Originally, these businesses were set up as legal partnerships in which the partners were entitled to a share of the profits of the enterprise. The name has remained even though many of these...

. Some firms use titles like "counsel," "special counsel," and "senior counsel" for the same concept. According to ABA Formal Opinion 90-357 the term "of counsel" is to describe "a close, regular, personal relationship."

Four American Bar Association definitions

Formal Opinion 90-357 of the American Bar Association

American Bar Association

The American Bar Association , founded August 21, 1878, is a voluntary bar association of lawyers and law students, which is not specific to any jurisdiction in the United States. The ABA's most important stated activities are the setting of academic standards for law schools, and the formulation...

 provides four acceptable definitions of the term:

• A part-time practitioner who practices law in association with a firm, but on a basis different from that of the mainstream lawyers in the firm. Such part-time practitioners are sometimes lawyers who have decided to change from a full-time practice, either with that firm or with another, to a part-time one, or sometimes lawyers who have changed careers entirely, as for example former judges or government officials.
• A retired partner of the firm who, although not actively practicing law, nonetheless remains associated with the firm and available for occasional consultation.
• A lawyer who is, in effect, a probationary partner-to-be: usually a lawyer brought into the firm laterally with the expectation of becoming partner after a relatively short period of time.
• A permanent status in between those of partner and associate, having the quality of tenure
  Tenure
  Tenure commonly refers to life tenure in a job and specifically to a senior academic's contractual right not to have his or her position terminated without just cause.-19th century:...
  
  , or something close to it, and lacking that of an expectation of likely promotion to full partner status.

Conflicts of interest

The title of "of counsel" carries with it particular ethical

Legal ethics

Legal ethics encompasses an ethical code governing the conduct of persons engaged in the practice of law and persons more generally in the legal sector.-In the United States:...

 responsibilities. For instance, for the purposes of a conflict of interest

Conflict of interest

A conflict of interest occurs when an individual or organization is involved in multiple interests, one of which could possibly corrupt the motivation for an act in the other....

, a legal relationship sufficient to permit the title of "of counsel" is also able to create conflicts.

Other uses

Some firms also use the term to refer to attorneys hired on a temporary basis to assist with a particular case. However, because "of counsel" describes "a close, regular, personal relationship," temporary lawyers used by law firms to engage in document reviews for a specific project or for limited duration are not "of counsel."