The English loanword cheongsam comes from chèuhngsàam, the Cantonese pronunciation of the Shanghainese term zǎnze or zansae (長衫, 'long shirt/dress'), by which the original tight-fitting form was first known. The Shanghainese name was somewhat in contrast with usage in Mandarin and other Chinese dialects, where chángshān (the Mandarin pronunciation of 長衫) refers to an exclusively male dress (see changshan) and the female version is known as a qipao.
In Hong Kong, where many Shanghai tailors fled to after the Communist takeover of the Mainland, the word chèuhngsàam may refer to either male or female garments. The word keipo (qipao) is either a more formal term for the female chèuhngsàam, or is used for the two-piece cheongsam variant that is popular in China. Traditionally, usage in Western countries mostly followed the original Shanghainese usage and applies the Cantonese-language name cheongsam to a garment worn by women.
When the Manchu ruled China during the Qing Dynasty, certain social strata emerged. Among them were the Banners (qí), mostly Manchu, who as a group were called Banner People (旗人 pinyin: qí rén). Manchu women typically wore a one-piece dress that retrospectively came to be known as the qípáo (旗袍 or banner gown). The generic term for both the male and the female forms of Manchu dress, essentially similar garments, was chángpáo (長袍). The qipao fitted loosely and hung straight down the body, or flared slightly in an A-line. Under the dynastic laws after 1636, all Han Chinese in the banner system were forced to wear a queue and dress in Manchurian qipao instead of traditional Han Chinese clothing (剃发易服), under penalty of death (along with the July 1645 edict (the "haircutting order") that forced all adult Han Chinese men to shave the front of their heads and comb the remaining hair into a queue, on pain of death). Until 1911, the changpao was required clothing for Chinese men of a certain class, but Han Chinese women continued to wear loose jacket and trousers, with an overskirt for formal occasions. The qipao was a new fashion item for Han Chinese women when they started wearing it around 1925.
A woman in the traditional loose fitting baggy qipao worn with an over jacketThe original qipao was wide and loose. It covered most of the woman's body, revealing only the head, hands, and the tips of the toes. The baggy nature of the clothing also served to conceal the figure of the wearer regardless of age. With time, though, the qipao were tailored to become more form fitting and revealing. The modern version, which is now recognized popularly in China as the "standard" qipao, was first developed in Shanghai in the 1920s, partly under the influence of Beijing styles. People eagerly sought a more modernized style of dress and transformed the old qipao to suit their tastes. Slender and form fitting with a high cut, it had great differences from the traditional qipao. However, it was high-class courtesans and celebrities in the city that would make these redesigned tight fitting qipao popular at that time. In Shanghai it was first known as zansae or "long dress" (長衫 - Mandarin Chinese: chángshān, Shanghainese: zansae, Cantonese: chèuhngsàam), and it is this name that survives in English as the "cheongsam".
The modernized version is noted for accentuating the figures of women, and as such was popular as a dress for high society. As Western fashions changed, the basic cheongsam design changed too, introducing high-necked sleeveless dresses, bell-like sleeves, and the black lace frothing at the hem of a ball gown. By the 1940s, cheongsam came in a wide variety of fabrics with an equal variety of accessories.
The 1949 Communist Revolution curtailed the popularity of the cheongsam and other fashions in Shanghai, but the Shanghainese emigrants and refugees brought the fashion to Hong Kong where it has remained popular. Recently there has been a revival of the Shanghainese cheongsam in Shanghai and elsewhere in Mainland China; the Shanghainese style functions now mostly as a stylish party dress.