A badge was originally simply a mark or emblem, rather than an object type in its own right (perhaps from the Anglo-French bage, meaning emblem). We now use it to mean an object type which is primarily a decodable sign, and whose form does not fit into any other object type such as BROOCH, MOUNT or HARNESS PENDANT. Badges can have many forms; they can be sewn on via loops, or held by a loop through cloth and a separate pin on the reverse like a modern military ‘brass’, or can have a pin but no catch.
Badges are not known before the medieval period. The most common type of medieval badge is the pilgrim badge, and this has its own object type – PILGRIM BADGE, which should be used for pilgrim souvenirs, whether attached by sewing or by a pin. The other main type of medieval badge is a livery badge, also called a secular badge, often incorporating heraldic elements; these continue in use into the post-medieval period.
A modern ‘badge’ with a pin, catch and a decorative element – like those that say ‘PREFECT’ or ‘I AM 7’ – is of course technically a brooch, and so BROOCH should be used as the object type.