GOWNS
A gown referred to a loose outer garment which was worn from knee to full length worn by both men and women in Europe from the early middle ages to the seventeenth century. Now gown refers to woman's garment comprising of a bodice and attached skirt.
If you talk about woman’s fashion then gown refers to a one piece garment. It comes with a close fitting bodice with long flared skirt which is normally worn on formal occasions. It is even worn during ceremonial occasions.
Gowns are available in several styles, designs and colors for different occasions. This site talks about several gown options which you have.