A bra, short for brassiere or brassière (US: , UK: or ; French: [bʁasjɛʁ]), is a form-fitting undergarment designed to support or cover a woman's breasts. Bras are designed for a variety of purposes, including enhancing breast size, creating cleavage, or for other aesthetic or practical considerations. Swimsuits, camisoles, and backless dresses may have built-in breast support with supportive bra cups. Nursing bras are designed to facilitate breastfeeding. Some people have a medical and surgical need for brassieres, but most wear them for fashion or cultural reasons. There is no evidence that bras prevent breasts from sagging and one study even suggests the opposite (weakening of the breasts supportive tissue), with the exception of wearing them during sports exercices.
Bras have gained importance beyond their mere functionality as a garment. Women's choices about what kind of bra to wear are consciously and unconsciously affected by social perceptions of the ideal female body shape, which changes over time. Bras have become a fashion item and cultural statement that are sometimes purposefully revealed by the wearer or even worn as outerwear.
Bras are complex garments made of many parts. Manufacturing standards assume idealized, standard breast shapes and sizes that don't match most bodies. Companies use vanity sizes, influencing the purchase of sizes that give the impression the wearer is slimmer or more buxom. In addition, international manufacturing standards and measurement methods vary widely. Due to these challenges, many people have a hard time finding a correctly fitting bra. When they do find one that appears to fit, their tendency is continuing wearing the same bra size despite weight gain or loss. All of these factors result in up to 85 percent of those women who wear bras choosing and wearing the wrong size. Due to the difficulty in finding a correctly fitting bra, a majority of women commonly experience discomfort while wearing a bra.
Some have protested societal expectations and sometimes school and workplace dress codes that require women to wear support garments. As early as 1873, the author Elizabeth Stuart Phelps advocated that women burn their corsets. This was echoed in 1968 at the protest during the Miss America pageant when women symbolically threw a number of feminine products into a large trash can. A reporter conflated their protest with Vietnam-era men who burned their draft cards, creating the trope of bra-burning feminists.