Black’s Law Dictionary 1st Edition, page 105:
ATTORNEY IN FACT. A private attorney authorized by another to act in his place and stead, either for some particular purpose, as to do a particular act, or for the transaction of business in general, not of a legal character. This authrity is conferred by an instrument in writing, called a “letter of attorney,” or more commonly a “power of attorney.” Bae. Abr. “Attorney;” Story, Ag. § 25.
Black’s Law Dictionary 8th Edition, page 392:
attorney. 1. Strictly, one who is designated to transact business for another; a legal agent. — Also termed at-torney-in-fact; private attorney. 2. A person who practices law; LAWYER. — Also termed (in sense 2) attor-ney-at-law; public attorney. Cf. COUNSEL. — Abbr. att’y. Pl. attorneys.[Cases: Attorney and Client 63. C.J.S. Attorney and Client §§ 165–166, 179–181, 234.]