Cosplay attendee in her costume.
Cosplay, a contraction of the words costume play, is a performance art in which participants called cosplayers wear costumes and fashion accessories to represent a specific character.
Cosplayers often interact to create a subculture and a broader use of the term "cosplay" applies to any costumed role-playing in venues apart from the stage. Any entity that lends itself to dramatic interpretation may be taken up as a subject and it is not unusual to see genders switched.
Favorite sources include manga and anime, comic books and cartoons, video games, and live-action films and television series.