Quick search by citation:

18 U.S. Code § 8 - Obligation or other security of the United States defined

The term “obligation or other security of the United States” includes all bonds, certificates of indebtedness, national bank currency, Federal Reserve notes, Federal Reserve bank notes, coupons, United States notes, Treasury notes, gold certificates, silver certificates, fractional notes, certificates of deposit, bills, checks, or drafts for money, drawn by or upon authorized officers of the United States, stamps and other representatives of value, of whatever denomination, issued under any Act of Congress, and canceled United States stamps.

(June 25, 1948, ch. 645, 62 Stat. 685.)
Historical and Revision Notes

Based on title 18, U.S.C., 1940 ed., § 261 (Mar. 4, 1909, ch. 321, § 147, 35 Stat. 1115; Jan. 27, 1938, ch. 10, § 3, 52 Stat. 7).

The terms of this section were general enough to justify its inclusion in this chapter rather than retaining it in the chapter on “Counterfeiting” where the terms which it specifically defines are set out in sections 471–476, 478, 481, 483, 492, and 504 of this title.

Words “Federal Reserve notes, Federal Reserve bank notes” were inserted before “coupons” because such notes have almost supplanted national bank currency.

Minor changes were made in phraseology.