The popular single piece long dress piece dress comes with an undefined waistline and hangs a little loose on the body. As the dress can make your figure appear straight and lanky, it is perfect for women with hefty or heavy body types but can be pulled on with ease by women with any body type. One-Piece is clothing for women of a shape in which the upper garment and the skirt are connected together. One-piece, bifurcated garments covering the upper and lower body, like an overall or a jumpsuit. For one-piece, non-bifurcated garments see Dresses, Gowns, and Robes and cloaks. I usually wear a bra and panties under a one piece dress unless it's backless then it's just panties. I wear a bra and underwear. At the beginning of the manga and anime, Pirate King Gol D. Roger confirms the existence of the mythological treasure known as the One Piece. The show is called One Piece because Luffy wants to find the One Piece and become the next Pirate King.