A hairnet, or sometimes simply a net or caul, is a small, often elasticised, fine net worn over long hair to hold it in place. It is often worn by food service workers to prevent hair from contaminating the food. A snood is similar but a looser fit and with a much coarser mesh.

Evidence has been found of hairnets as far back as ancient Greece,^{[dead link]} further evidence are known from archaeological finds of Iron Age bog bodies from Denmark and Germany. Hairnets were worn from the 13th century onwards in Germany and England and are shown in illustrations from this period often worn with a wimple. They were made from extremely fine silk and edged with bands of either finger-weaving or tablet-weaving.

Ena Sharples, a character in the UK soap opera Coronation Street between 1960 and 1980, was famous for wearing a hairnet.

Hairnets are part of normal attire for female horse riders and are worn in most equestrian disciplines, including dressage, eventing, show jumping and hunting. Organisations such as the Pony Club encourage their young members to become accustomed to wearing hairnets when around horses, not only to ensure a neat and elegant appearance, but also to eliminate any danger of scalping should the rider fall off and the horse tread on loose hair.

Christopher Wesson Bosh (born March 24, 1984) is an American professional basketball player who plays power forward for the Miami Heat in the National Basketball Association (NBA).

A high school "Mr. Basketball" in Texas, Bosh left college at Georgia Tech after one season with the Georgia Tech Yellow Jackets men's basketball team to enter the 2003 NBA Draft. He was selected fourth overall by the Toronto Raptors in a very competitive draft class. While at Toronto, Bosh emerged as one of the young stars in the league; he became a five-time NBA All-Star, was named to the All-NBA second team once, appeared for the US national team (with whom he won a gold medal at the 2008 Olympics), and took over former fan-favorite Vince Carter as the face and leader of the Raptors franchise. In the 2006–07 season, Bosh led the Raptors to their first NBA Playoffs berth in five years, and their first ever division title. He left Toronto as its all-time leader in points, rebounds, blocks, double doubles, free throws made and attempted, and minutes played.

Long hair is a hairstyle. Exactly what constitutes long hair can change from culture to culture, or even within cultures. For example, a woman with chin-length hair in some cultures may be said to have short hair, while a man with the same length of hair in some of the same cultures would be said to have long hair.

Scientists view long hair as playing a large part in natural selection among many species, since long, thick and healthy hair or fur is frequently a sign of fertility and youth. As hair grows slowly, long hair reveals several years of a person's health status and reproductive fitness. Hair length is significantly correlated with female attractiveness, as rated by men as well as women. Hair length and quality can act as a cue to especially a woman's youth and health, signifying reproductive potential. The prevalence of trichophilia (hair partialism or fetischism) is 7% in the population, and very long hair is a common subject of devotion in this group.

Ways of life often viewed as more rigid, such as soldiers and religious cultures, often have explicit rules regarding hair length. For example, Buddhist monks shave their heads as part of their order of worship. Even outside religious structures, cultures often associate male long hair with ways of life outside of what is culturally accepted. Subservient cultures, for example, are sometimes detected by their rulers through hair length, as was the case with the Gaelic Irish under English rule and the Moors under Spanish rule in Medieval Spain.