Rack Supporters are a type of clothing accessory that provide additional support to the wearer. They are typically made of elastic material and are worn around the chest, under the arms, and around the back. The term 'Rack Supporters' is often used interchangeably with the term 'bras, ' which is a four-letter word that is the solution to this crossword puzzle. Bras are designed to provide support and comfort to the wearer, as well as to enhance the appearance of the wearer's figure.