Wiktionary
n. Items such as covers and associated material illustrating historical episodes of postal systems.
Wikipedia
Postal history is the study of postal systems and how they operate and, or, the study of the use of postage stamps and covers and associated postal artifacts illustrating historical episodes in the development of postal systems. The term is attributed to Robson Lowe, a professional philatelist, stamp dealer and stamp auctioneer, who made the first organised study of the subject in the 1930s and described philatelists as "students of science", but postal historians as "students of humanity". More precisely, philatelists describe postal history as the study of rates, routes, markings, and means (of transport).
Usage examples of "postal history".
This Byron, whose only romantic inclination had to do with postal history, had a round face to match his round body.