A fair is a gathering of people to display or trade produce or other goods, to parade or display animals and often to enjoy associated carnival or funfair entertainment. Activities at fairs vary widely. Some are important showcases for businessmen in agricultural, pastoral or horticultural districts because they present opportunities to display and demonstrate the latest machinery on the market.
Fairs are also known by many different names around the world, such as agricultural show, carnival, fete or fête, county or state fair, festival, market and show, etc. Flea markets are sometimes incorporated into a fair.

Fayre
The fair is an ancient tradition, and many communities have long had dedicated fairgrounds; others hold them in a variety of public places, including streets and town squares, or even in large private gardens. Fairs are often held in conjunction with a significant event, such as the anniversary of a local historical event, a seasonal event such as harvest time, or with a holiday such as Christmas.
That part of a fair (commonly an American fair such as a county or state fair) where amusement park rides, entertainment and fast food booths are concentrated is called the midway, after the avenue of amusements at the 1893 World's Columbian Exposition in Chicago.

History
See Court of Piepowders
Because of the great numbers of people attracted by fairs they were often the scenes of riots and disturbances, so the privilege of holding a fair was granted by royal charter. At first they were only allowed in towns and places of strength, or where there was some bishop, sheriff or governor who could keep order. In time, various benefits became attached to certain fairs, such as granting people the protection of a holiday, and allowing them freedom from arrests in certain circumstances. The officials were authorised to do justice to those that came to their fair; eventually even the smallest fair would have had a court to adjudicate on offences and disputes arising within the fairground, which was called a pye powder court (from Old French pied pouldre, an itinerant trader, which literally means "dusty feet"), or pedes pulverizati.

Free fairs
brandy

World's Fair
State fair
Trade fair
Street fair
Agricultural show
Auto fair
Christmas Without Cruelty Fayre
Court jester