megafan

plural megafans

1. geographyA very large mass of clastic sediment deposited by a laterally mobile river system that fans out from the outlet from a large mountainous drainage network.

   The dynamics of river systems in megafan environments may strongly influence the fragmentation and reconnection of riverine habitats, and therefore by implication, the diversification and distribution of freshwater organisms.

   2011, James S. Albert, Roberto E. Reis, Historical Biogeography of Neotropical Freshwater Fishes, →ISBN, page 197

2. informalAn obsessively enthusiastic fan.

   Nathan Kaufman, 25, another Radiohead megafan, said of the plan, “I got geeked about it immediately.”

   2007 October 4, Melena Ryzik, “Radiohead Fans, Guided by Conscience (and Budget)”, in New York Times

   Synonyms: stan, superfan, trufan, uberfan