Sportswear is an American fashion term originally used to describe separates, but which since the 1930s has come to be applied to day and evening fashions of varying degrees of formality that demonstrate a specific relaxed approach to their design, while remaining appropriate for a wide range of social occasions. The term is not necessarily synonymous with activewear, clothing designed specifically for participants in sporting pursuits. Although sports clothing was available from European haute couture houses and "sporty" garments were increasingly worn as everyday or informal wear, the early American sportswear designers were associated with ready-to-wear manufacturers. While most fashions in America in the early 20th century were directly copied from, or influenced heavily by Paris, American sportswear became a home-grown exception to this rule, and could be described as the American Look. Sportswear was designed to be easy to look after, with accessible fastenings that enabled a modern emancipated woman to dress herself without a maid's assistance.

History of fashion design refers specifically to the development of the purpose and intention behind garments, shoes, accessories, and their design and construction. The modern industry, based around firms or fashion houses run by individual designers, started in the 19th century with Charles Frederick Worth who, beginning in 1858, was the first designer to have his label sewn into the garments he created.