A chemise is essentially a camisole that ends past the waist. Usually worn as an undergarment.
In modern usage, a chemise is generally a woman's garment that vaguely resembles the older shirts but is typically more delicate, and usually provocative. Most commonly the term refers to a loose-fitting, sleeveless undergarment or type of lingerie which is unfitted at the waist. It can also refer to a short, sleeveless dress that hangs straight from the shoulders and fits loosely at the waist. A chemise typically does not have any buttons or other fasteners and is put on by either dropping it over the head or stepping into it and lifting it up.
As lingerie, a chemise is similar to a babydoll, which is also a short, loose-fitting, sleeveless garment. Typically, though, babydolls are more loose-fitting at the hips and are generally designed to more resemble a young girl's nightgown, although many modern styles have added various sexualizing features.