A fandom is a subculture composed of fans characterized by a feeling of camaraderie with others who share a common interest. Fans typically are interested in even minor details of the objects of their fandom and spend a significant portion of their time and energy involved with their interest, often as a part of a social network with particular practices, differentiating fandom-affiliated people from those with only a casual interest.
A fandom can grow around any area of human interest or activity. The subject of fan interest can be narrowly defined, focused on something like a franchise or an individual celebrity, or encompassing entire hobbies, genres or fashions. While it is now used to apply to groups of people fascinated with any subject, the term has its roots in those with an enthusiastic appreciation for sports. Merriam-Webster's dictionary traces the usage of the term back as far as 1903.[1]
Many fandoms are overlapped. There are a number of large conventions that cater to fandom such as film, comics, anime, television shows, cosplay, and the opportunity to buy and sell related merchandise. Annual conventions such as San Diego Comic-Con, Wondercon, Dragon Con, and New York Comic Con are some of the more well-known and highly attended events that cater to overlapping fandoms.