Postal worker
A postal worker is one who works for a post office, such as a mail carrier. In the U.S., postal workers are represented by the American Postal Workers Union, part of the AFL-CIO. In Canada, they are represented by the Canadian Union of Postal Workers and in the United Kingdom by the Communication Workers Union.
The phrase wasn't very often used until a spate of workplace violence incidents by postal workers in the late 1980s made headlines. The incidents also led to the coining of the phrase going postal.
Postal workers in fiction