fandom: fans collectively, as of a motion-picture star or a professional game or sport.

Agree with DP. One of the meanings of the noun-forming suffix "-dom" is "a collection of persons" (compare: officialdom). This suffix also indicates a state or condition (compare: boredom, freedom). So "fandom" means both "admirers in common" and "adoration".

Thank you guys. i get that word from a video.

What is that mean?I heard and read first time.I am wondering,too:)