Bank. Each agent, agency, branch or office within the United States of any person doing business in one or more of the capacities listed below:
(1) A commercial bank or trust company organized under the laws of any State or of the United States;
(2) A private bank;
(3) A savings and loan association or a building and loan association organized under the laws of any State or of the United States;
(4) An insured institution as defined in section 401 of the National Housing Act;
(5) A savings bank, industrial bank or other thrift institution;
(6) A credit union organized under the law of any State or of the United States;
(7) Any other organization (except a money services business) chartered under the banking laws of any state and subject to the supervision of the bank supervisory authorities of a State;
(8) A bank organized under foreign law;
(9) Any national banking association or corporation acting under the provisions of section 25(a) of the Act of Dec. 23, 1913, as added by the Act of Dec. 24, 1919, ch. 18, 41 Stat. 378, as amended (12 U.S.C. 611-32).
31 CFR § 1010.100
When used in this chapter and in forms prescribed under this chapter, where not otherwise distinctly expressed or manifestly incompatible with the intent thereof, terms shall have the meanings ascribed in this subpart. Terms applicable to a particular type of financial institution or specific part or subpart of this chapter are located in that part or subpart. Terms may have different meanings in different parts or subparts.