term used by the <#usps=United States Postal Service> for stamps intended for use on mail.

<#uspod=USPOD> employee responsible for receiving and accounting for deliveries of completed stamps from nineteenth century private security printers and sending them to post offices as needed.

a rotary perforator with one long horizontal row of pins and numerous short vertical columns of pins.  This pin format resembles a comb.  A single rotation perforates three sides of each of the stamps in a single row.

a train which consists exclusively of mail cars. The first one operated between New York and Chicago.

<#postage> purchased from an internet vendor and printed at a customer’s convenience.