Fashion is a multifaceted industry that encompasses a broad range of styles, aesthetics and trends. It is a global business that encompasses designers, manufacturers, retailers, marketers and others, with a worldwide network of businesses supporting millions of jobs. Fashion can also be seen as a form of self-expression and identity, or as a means to identify with a particular culture or community. It can be used as a tool for social change, such as when women in Iran wear headscarves to protest against the Islamic regime. It can also serve as a sign of status, as when a wealthy person is seen wearing designer clothes.
In order for something to be considered fashion, it must be shared and followed by multiple people, a phenomenon known as mass diffusion. This can occur through a number of channels, including cultural icons (such as musicians and film stars), fashion journalists, or by word of mouth. In some cases, a new style may be introduced by a fashion innovator and adopted by fashion leaders (also called influencers), who promote it through their social media platforms. In other cases, a new style might be introduced by members of a specific group, such as blue-collar workers or teenagers, and then adopted by the larger population.
As a result, it is often difficult to trace the origin of a fashion trend. Some theories of fashion suggest that higher socioeconomic status individuals set the trends, which trickle down to lower classes and social groups.