§ 3621. Applicability; definitions
(a)
Applicability.—
This subchapter shall apply with respect to—
subject to any changes the Postal Regulatory Commission may make under section
3642.
(b)
Rule of Construction.—
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.