marcophily

thumb|A study of the postmarks of Prague between 1850 and 1888.

Marcophily, occasionally called Marcophilately, is the specialised study and collection of postmarks, cancellations and postal markings applied by hand or machine on mail that passes through a postal system and applied by the postal operator through whose domain they pass. Commatology was a term used prior to World War II but is rarely used today.