The bikini is typically a women's two-piece swimsuit. One part of the attire covers the breasts and the other part covers the crotch and part of or the entire buttocks, leaving an uncovered area between the two. Merriam--Webster describes the bikini as "a woman's scanty two-piece bathing suit" or "a man's brief swimsuit". It is often worn in hot weather, while swimming or sunbathing. The shapes of both parts of a bikini resemble women's underwear, and the lower part can range from revealing thong or g-string to briefs.
While two-piece bathing suits had been worn on the beach before, the modern bikini was invented by French engineer Louis Réard in 1946. He named it after Bikini Atoll in the Pacific, the site of the Operation Crossroads nuclear weapon tests in July that year.
The bikini is perhaps the most popular female beachwear around the globe, according to French fashion historian Olivier Saillard due to "the power of women, and not the power of fashion". As he explains, "The emancipation of swimwear has always been linked to the emancipation of women. By the mid 2000s, bikinis had become a $811 million business annually, according to the NPD Group, a consumer and retail information company. The bikini has boosted spin-off services like bikini waxing and the sun tanning industries.
Predecessors of the bikini date to antiquity, in Çatalhöyük and the Greco-Roman world. Art dating from the Diocletian period (286--305 AD) in Villa Romana del Casale, Sicily depicts women in garments resembling bikinis in mosaics on the floor. The images of ten women, dubbed the "Bikini Girls", exercising in clothing that would pass as bikinis today are the most replicated mosaic among the 37 million colored tiles at the site. Archeological finds, particularly in Pompeii, show the Roman goddess Venus wearing a bikini. A statue of Venus in a bikini was found in a cupboard in the southwest corner in Casa della Venere, others were found in the front hall. A statue of Venus was recovered from the tablinum of the House of Julia Felix, and another from an atrium at the garden at Via Dell'Abbondanza.
The groundwork for the modern bikini began to be laid in 1907, when Australian swimmer and performer Annette Kellerman was arrested on a Boston beach for wearing a form-fitting one-piece swimsuit, which became an accepted beach attire for women by 1910. In 1913, inspired by the introduction of women into Olympic swimming, designer Carl Jantzen made the first functional two-piece swimwear, a close-fitting one-piece with shorts on the bottom and short sleeves on top.
By the 1930s, necklines plunged at the back, sleeves disappeared and sides were cut away. Hollywood endorsed the new glamour with films such as Neptune's Daughter in which Esther Williams wore provocatively named costumes such as "Double Entendre" and "Honey Child".
With new materials like latex and nylon, by 1934 the swimsuit started hugging the body and had shoulder straps to lower for tanning.