Panniers or side hoops are women's undergarments worn in the 18th century to extend the width of the skirts at the side while leaving the front and back relatively flat. This provided a panel where woven patterns, elaborate decorations and rich embroidery could be displayed and fully appreciated.
The style originated in Spanish court dress of the 17th century, familiar in portraits by Velázquez. The fashion spread to France and from there to the rest of Europe after c. 1718–1719, when some Spanish dresses had been displayed in Paris.
The earlier form of the pannier took the shape similar to a 19th century crinoline. They were wide and domed in circumference.
By mid-18th century it had been developed into the robe à la française, which ensured that a woman took up three times as much space as a man and always presented an imposing spectacle. At their most extreme, in the French court of Marie Antoinette, panniers could extend the skirt several feet at each side. By the 1780s, panniers were normally worn only to very formal gowns and within court fashion.
See also 
- R. Broby-Johanssen (in Swedish): Kropp och kläder. Klädedräktens historia (Body and clothes. The history of clothing) (1994)
|Wikimedia Commons has media related to: Pannier (clothing)|
- Eighteenth-Century Silhouette and Support at the Metropolitan Museum of Art
- The Costumer's Manifesto: The Cut of Women's Clothes 1700–1800