noun
dunce cap; fool's cap
A conical paper hat historically placed on the head of a slow or misbehaving student as a punishment. The term is a direct loan from English, and the concept is understood in Japan primarily through Western cultural references.
昔の学校では、いたずらをした生徒にダンスキャップをかぶせる罰があった。
In old schools, there was a punishment of making a misbehaving student wear a dunce cap.