Just because it was my first thought at one time - I wanted to visually clarify one of the fest items. Fashionable ladies are not suddenly walking around wearing panty waist cinchers.
In Fantasy/Medieval garments - they are usually the belt/sash/chain worn about the waist of a gown, most often seen with Kirtles (gown most commonly used in Fantasy/Medieval art where the ladies are wearing something other than chain mail bikinis). A girdle is probably the more correct term that some people end up refering to as a "hip chain" or "sash".
Here are a few links for pictures if it helps visually:
http://www.themedievalmarket.com/girdle.html
http://www.polyhymniaconcepts.com/wedding.htm
(4th and 5th gowns)
~~ Ahnoui's Bazaar: http://drbazaar.googlepages.com ~~
Featuring Eeary Forged Armor, Drevid Forged Weapons, Leathers, Bucklers, Arrows & More!
~~ DR Script Repository: http://scripts.whistlethis.com/index.php ~~