Cosplay, short for "costume play," is the practice of dressing as a fictional character, usually with handmade or heavily modified costumes, wigs, and props, for conventions, photography, and performance. The word was coined in Japan in the 1980s.
Cosplay is a craft discipline wearing a fandom's clothes. Serious cosplayers pattern their own garments, style wigs, build props from foam and thermoplastics, and learn makeup, photography, and performance, then wear the result for a day at a convention. The masquerade competitions at major events judge construction the way a craft fair does, because that is what they are.
The practice is also social infrastructure. Conventions are the physical home of a mostly online fandom, and a costume is an introduction that works at twenty paces: it announces a favourite series, invites photos and conversation, and turns strangers into co-fans on sight.
Japan formalized the word, the world's largest cosplay gathering is held in Nagoya, and the culture is thoroughly global now. This site covers cosplay as vocabulary: it is part of how fandom happens in the world, and a reader who knows the term knows what the crowds at a convention are doing and why it matters to them. Photography is half the modern practice: a costume is built to be worn for a day and photographed forever, and skilled cosplay photographers are credited collaborators in the scene.
In use"Six months of foam work, one wig styled three times, and a hallway full of photo requests: that is cosplay."