Chiffon, which is
French for
rag, is a lightweight
sheer material with a slightly rough feel to it. It can be made from
cotton,
silk or
synthetic fibers, but is usually associated with silk and can be dyed to most any shade you like.
You see chiffon most commonly in evening wear, especially as on overlay, giving a elegant and dreamy appearance to the gown. It is also a popular fabric used in blouses, scarves and lingerie. It is not, however, an easy fabric to work with because of its lightweight and slippery nature, but it's worth the extra effort because you can create some really beautiful garments with chiffon.
Sources:
Personal experience
SRFabrics.com
Fabrics.net