The term 'Dress Shirt Fastener' is often referred to as a STUD, which is a four-letter word. A dress shirt fastener is a type of clothing accessory used to secure the front of a dress shirt closed. It is typically made of metal and is usually round or oval in shape. It is inserted through two holes in the shirt and then secured with a backing piece. Dress shirt fasteners are an important part of formal attire and are often seen on tuxedo shirts.