What is a "dunce cap"?

A dunce cap, also known as a "dunce hat," is a conical hat that was historically worn by students as a form of punishment for misbehaving or not performing well in school. It is typically made of paper or felt and is often brightly colored or decorated with a large letter "D" for "dunce." The dunce cap is commonly associated with old-fashioned classroom discipline, and its use has largely fallen out of favor in modern times due to concerns about its potentially harmful effects on a student's self-esteem. Today, the term "dunce cap" is often used more broadly to refer to any kind of public embarrassment or shaming.