Original: Fandom (from the noun fan and the affix -dom, as in kingdom, freedom, etc.) is a term used to refer to a subculture composed of fans characterized by a feeling of sympathy and camaraderie with others who share a common interest.
Simplified: Fandom (from the noun fan and the affix -dom, as in kingdom, dukedom, etc.) or Fanbase is a name used for a group of people (called "fans") who are interested in something.