It is a big group of people that use multiple things and/or people to put in their fandom such as~ South Park and Phan.
Many people love to create fandom names and ship names like Stenny (Stan and Kenny from South Park)
Also another definition is where fans of a specific subject name it in a certain way.
Me~ Im in the South Park Fandom!!!
Friend 1~ screw you I'm in the Phandom!!
Hottest boy~ I'm in the Basketball Fandom!!
Me and friend~ -facepalms- That's the wrong use of the word 'Fandom'
Person 1: Hey! I've been in the <Insert fandom here> fandom for years, it's been fun! Although I think I'm ready to move on, mind telling me where the exit it?
Fandom is a cultural phenomenon that has experienced increased participation alongside consumerism and postmodern society. Fandom refers to a variety of collective behaviors performed by persons who have strongly and socially identified with an aspect of consumer culture, mass media, or some other artifact or non-material culture. Collective behaviors may include being active in fandom social media sites, attending fandom events in public, dressing in a manner that expresses one's solidarity with an aspect of consumer culture, possessing and purchasing paraphernalia that confirms one's attachment to an aspect of consumer culture.
Fandom has been known to affect adult development over a person's life course in both positive and negative ways.
A fandom is a fan group connected by a Love for a certain book,movie,tv show,social media star, or musician. Most of the time the artist or star has a fandom name like Why Don’t We=Limelights. Or the fandom could have no name like the Dolan Twins.