§ 3621. Applicability; definitions

• (a) This subchapter shall apply with respect to—
  • (1) first-class mail letters and sealed parcels;
  • (2) first-class mail cards;
  • (3) periodicals;
  • (4) standard mail;
  • (5) single-piece parcel post;
  • (6) media mail;
  • (7) bound printed matter;
  • (8) library mail;
  • (9) special services; and
  • (10) single-piece international mail,
• (b) Mail matter referred to in subsection (a) shall, for purposes of this subchapter, be considered to have the meaning given to such mail matter under the mail classification schedule.