Yếm refers to an ancient Vietnamese bodice used primarily as an undergarment that was once worn by Vietnamese women across all classes. There exists a modern variant called "áo yếm", but the historical garment was simply called "yếm".
It is a simple garment with many variations from its basic form, which is a simple, usually diamond or square-cut piece of cloth draped over a woman's chest with strings to tie at the neck and back.
Áo bà ba (or Vietnamese silk pajamas) is a traditional Vietnamese costume. It is most associated with southern Vietnam, especially in rural areas.
The áo bà ba simply consists of a pair of silk pants and a long-sleeved, button-down silk shirt. The shirt will be somewhat long and split at the sides of the waist, forming two flaps. In the front of the shirt at the very bottom are typically two pockets.
The Áo tứ thân can be considered one of the oldest enduring Vietnamese cultural relics, having been worn widely by women centuries before the ao dai.As Vietnam expanded southward, the Áo tứ thân gradually became associated specifically with northern women.
In general; Vietnamese people dress conservatively. Although some young women wear more close-fitting; Western-style clothing; it is considered inappropriate to wear revealing clothes during the day. One Westerner teaching English in Viet Nam was advised to tuck her shirt into her trousers if she expected respect from her students. It is considered inappropriate for educated people to wear their shirts untucked.
Traditional costumes of the Vietnamese people tend to be very simple and modest. Men wear brown shirts and white trousers. Their headgear is simply a piece of cloth wrapped around the head and their footwear consists of a pair of plain sandals.