A fad is any form of behavior that develops among a large population and is collectively followed with enthusiasm for some period, generally as a result of the behavior's being perceived as novel in some way.[1] A fad is said to "catch on" when the number of people adopting it begins to increase rapidly. The behavior will normally fade quickly once the perception of novelty is gone.[1]

The specific nature of the behavior associated with a fad can be of any type including language usage, apparel, financial investment, and even food. Apart from general novelty, fads may be driven by emotional excitement, peer pressure, or even a desire to be outside social norms (counterculture).[2]

Though the term trend may be used interchangeably with fad, a fad is generally considered a fleeting behavior whereas a trend is considered to be a behavior that evolves into a relatively permanent change.[3]

1950s, the beatnik movement became a major fad that died out as its original proponents abandoned the movement. Though this fad, in and of itself, was short-lived, it is credited with giving birth to the hippie movement in the following decade, and with inspiring other social trends in the decades that followed.[4]