Badge

From Hpwiki

Badges in the wizarding world do the same as in the Muggle world - they indicate a function, role, or membership. In the Harry Potter novels, the following people wear badges:

• Prefects
• Members of the Inquisitorial Squad
• Slytherin students who want to ridicule the Gryffindor Quidditch team
• Hermione for the S.P.E.W.