Negligees are explicitly included in heading 6208 as intimate apparel, regardless of how sheer or decorative the fabric. They are not classified as outerwear. The subheading depends on the chief fiber by weight — man-made fibers (620892) or other materials (620899) are the most common.

A slip is an undergarment worn beneath outer clothing and is classified under 6208. A dress is an outer garment and falls under 6204. The distinction rests on intended use and retail presentation; a garment marketed and packaged as a slip is classified as such even if it could theoretically be worn as a dress.