phi‧lat‧e‧ly /fəˈlætəli/ noun [uncountable]
the activity of collecting stamps for pleasure
引用元：philately | ロングマン現代英英辞典でのphilatelyの意味 | LDOCE https://www.ldoceonline.com/jp/dictionary/philately
Philately (/fɪˈlætəliː/; fi-LAT-ə-lee) is the study of postage stamps and postal history. It also refers to the collection, appreciation and research activities on stamps and other philatelic products. Philately involves more than just stamp collecting or the study of postage; it is possible to be a philatelist without owning any stamps. For instance, the stamps being studied may be very rare or reside only in museums.
引用元：Philately – Wikipedia https://en.wikipedia.org/wiki/Philately
Notaphily is the study and collection of paper currency, and banknotes. A notaphilist is a collector of banknotes or paper money, particularly as a hobby.
引用元：Notaphily – Wikipedia https://en.wikipedia.org/wiki/Notaphily
Lepidopterology (from Ancient Greek λεπίδος (scale) and πτερόν (wing); and -λογία -logia.), is a branch of entomology concerning the scientific study of moths and the three superfamilies of butterflies. Someone who studies in this field is a lepidopterist or, archaically, an aurelian.
引用元：Lepidopterology – Wikipedia https://en.wikipedia.org/wiki/Lepidopterology
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.
Marcophilists are more interested in the details, style and design of the markings than why and where a letter was sent. Large cities that have many post offices offer great study opportunities due to the vast range of handstamps or machine cancellations in use over any time period. It offers vast study areas to select a topic from for study or collection.
引用元：Marcophily – Wikipedia https://en.wikipedia.org/wiki/Marcophily
Deltiology (from Greek δελτίον, deltion, diminutive of δέλτος, deltos, “writing tablet, letter”; and -λογία, -logia) is the study and collection of postcards. Professor Randall Rhoades of Ashland, Ohio, coined a word in 1945 that became the accepted description of the study of picture postcards. It initially took about 20 years for the name to appear in a dictionary. Compared to philately, the identification of a postcard’s place and time of production can often be an impossible task because postcards, unlike stamps, are produced in a decentralised, unregulated manner. For this reason, some collectors choose to limit their acquisitions to cards by specific artists and publishers, or by time and location.
引用元：Deltiology – Wikipedia https://en.wikipedia.org/wiki/Deltiology
A numismatist is a specialist in numismatics (“of coins”; from Late Latin numismatis, genitive of numisma). Numismatists include collectors, specialist dealers and scholars who use coins in object-based research. Although the term numismatics was first coined in English in 1829, people had been collecting and studying coins long before this, all over the world.
引用元：Numismatist – Wikipedia https://en.wikipedia.org/wiki/Numismatist