15 U.S.C. § 383 : Commerce And Trade — State Taxation Of Income From Interstate Commerce — Net Income Taxes — “Net Income Tax” Defined

For purposes of this chapter, the term “net income tax” means any tax imposed on, or measured by, net income.

(Pub. L. 86–272, title I, § 103, Sept. 14, 1959, 73 Stat. 556.)