the traditional costume of Vietnamese women, consisting of a long, high-necked, closefitting tunic split along the sides from waist to hem: it is worn over loosefitting trousers
See ao dai in American Heritage Dictionary 4
(ouˈ dī, ôˈ)
nounpl.ao dais
A traditional garment of Vietnamese women, consisting of a knee-length jacket with sides slit up to the hips, and worn over loose trousers.