Cosplay (???? kosupure?), short for “costume play”, is a type of performance art whose participants outfit themselves, with often-elaborate costumes and accessories, as a specific character. Characters are usually sourced in various Japanese and East Asian media, including manga, anime, tokusatsu, comic books, graphic novels, video games, and fantasy movies. Other sources include performers from J-pop, J-rock, Visual Kei, fantasy music stories (such as stories by the band Sound Horizon), novels, and objects from cyberspace or the real world that are unique and dramatic (especially if they have or can be given an anthropomorphic form).
Cosplay participants (“cosplayers”) form a subculture centered around wearing their costumes and reenacting scenes or inventing likely behavior inspired by their chosen sources. In some circles, the term cosplay has been broadened to include simply wearing a costume, without special consideration given to enacting characters in a performance context.
Aren’t you glad you asked?
One imagines this could go off.
[Image by mikemol, released on Flickr, published under Creative Commons By Attribution licence]