(a) As used in this subchapter and section 321 of this title the term "State bank" means any bank, banking association, trust company, savings bank (other than a mutual savings bank), or other banking institution which is engaged in the business of receiving deposits and which is incorporated under the laws of any State, any Territory of the United States, Puerto Rico, or the Virgin Islands, or which is operating under the Code of Law for the District of Columbia (except a national banking association). (b) For purposes of merger or consolidation under this subchapter and section 321 of this title the term "national banking association" means one or more national banking associations, and the term "State bank" means one or more State banks.