A more thorough explanation:

Definition: An attorney who is affiliated with a law firm, but not employed as a partner or associate. This designation often identifies a semi-retired partner, an attorney who occasionally uses the office for a few clients, or one who only consults on certain matters.

Example: John is a lawyer who used to be a partner at a law firm, but now he only works there as of counsel. He comes in a few times a week to help with cases and give advice, but he is not a full-time employee.

Explanation: This example illustrates how an attorney can be affiliated with a law firm without being a partner or associate. John is a semi-retired partner who still wants to be involved in the legal field, but not on a full-time basis. By being of counsel, he can still use the resources of the law firm and help out with cases when needed.