Cosplay is a marriage of the phrases ‘gown’ and ‘play’, a form of performance art wherein contributors called cosplayers put on costumes and style accessories to represent a specific person.
https://www.ccosplay.com/
When I think about this phenomenon, the primary issue that involves thoughts is a % of nerds dressing up like video game or comedian book characters. It is deeply uncool, but by some means the practice and related terminology have entered pop culture’s lexicon.