Definition of "mailpiece"

Each mailjob is composed of pages that go into a single envelope. These are called mailpieces.

1995 April, Anthony F. Stuart, Technical Association of the Graphic Arts, Proceedings, page 442

The name and return address of the authorized nonprofit organization must be either on the outside of the mailpiece or in a prominent location

2002, Bruce R. Hopkins, The Law of Fundraising, page 316