Other forms: valances
The flouncy bit of fabric at the top of a window is a valance. Sometimes, people use a valance to cover an unattractive curtain rod.
Don't confuse valance with valence — you'll only use the latter when you're talking about atoms in chemistry class. A valance, on the other hand, is a decorative piece of drapery, part of a fairly elaborate window treatment. In Victorian times, valances were extremely popular, used by many home decorators. Experts suspect this word comes from the Old French valer, "go down or let down."