This term refers to trends that are inspired by pop culture which in turn inspire a fashion movement. Examples of trends inspired by people on the street are London's Teddy Boys and the beat look of the 1950s, hippies of the 1960s, punk style of the 1970s, goth style of the 1980s, the fitness craze and grunge of the 1990s, and the hip-hop style of 2000. Many big-name designers such as Mary Quant, Vivienne Westwood, Yves Saint Laurent, Dolce & Gab-bana, Sonia Rykiel, and Calvin Klein have been known to get fashion direction and inspiration from observing street culture. Street style is the exact opposite of the trickle-down effect, which dates back to the Middle Ages when fashion was handed down from the noble class to the peasants. While replication of clothing worn by the wealthy elite continues, it is in direct opposition to this trend that inspiration for street style comes from "middle or lower class heroes." Biker jackets worn by the beat generation, denim jeans worn by hippies, and oversized hip-hop clothing worn by inner-city breakdancing kids are all examples of trends that emulated from the bottom up.
Historical Dictionary of the Fashion Industry. Francesca Sterlacci and Joanne Arbuckle.