The ball is a hard leather-seamed spheroid, with a circumference of 22.9 centimetres (9.0 in). The ball has a "seam": six rows of stitches attaching the leather shell of the ball to the string and cork interior. The seam on a new ball is prominent and helps the bowler propel it in a less predictable manner. During matches, the quality of the ball deteriorates to a point where it is no longer usable; during the course of this deterioration, its behaviour in flight will change and can influence the outcome of the match. Players will, therefore, attempt to modify the ball's behaviour by modifying its physical properties. Polishing the ball and wetting it with sweat or saliva is legal, even when the polishing is deliberately done on one side only to increase the ball's swing through the air, but the acts of rubbing other substances into the ball, scratching the surface or picking at the seam are illegal ball tampering.
One possible source for the sport's name is the Old English word "cryce" (or "cricc") meaning a crutch or staff. In Samuel Johnson's Dictionary, he derived cricket from "cryce, Saxon, a stick". In Old French, the word "criquet" seems to have meant a kind of club or stick. Given the strong medieval trade connections between south-east England and the County of Flanders when the latter belonged to the Duchy of Burgundy, the name may have been derived from the Middle Dutch (in use in Flanders at the time) "krick"(-e), meaning a stick (crook). Another possible source is the Middle Dutch word "krickstoel", meaning a long low stool used for kneeling in church and which resembled the long low wicket with two stumps used in early cricket. According to Heiner Gillmeister, a European language expert of Bonn University, "cricket" derives from the Middle Dutch phrase for hockey, met de (krik ket)sen (i.e., "with the stick chase"). Gillmeister has suggested that not only the name but also the sport itself may be of Flemish origin.
Male crickets establish their dominance over each other by aggression. They start by lashing each other with their antennae and flaring their mandibles. Unless one retreats at this stage, they resort to grappling, at the same time each emitting calls that are quite unlike those uttered in other circumstances. When one achieves dominance, it sings loudly, while the loser remains silent.
Crickets (also known as "true crickets"), of the family Gryllidae, are insects related to bush crickets, and, more distantly, to grasshoppers. The Gryllidae have mainly cylindrical bodies, round heads, and long antennae. Behind the head is a smooth, robust pronotum. The abdomen ends in a pair of long cerci; females have a long, cylindrical ovipositor. The hind legs have enlarged femora, providing power for jumping. The front wings are adapted as tough, leathery elytra, and some crickets chirp by rubbing parts of these together. The hind wings are membranous and folded when not in use for flight; many species, however, are flightless. The largest members of the family are the bull crickets, Brachytrupes, which are up to 5 cm (2 in) long.
Captive crickets are omnivorous; when deprived of their natural diet, they accept a wide range of organic foodstuffs. Some species are completely herbivorous, feeding on flowers, fruit, and leaves, with ground-based species consuming seedlings, grasses, pieces of leaf, and the shoots of young plants. Others are more predatory and include in their diet invertebrate eggs, larvae, pupae, moulting insects, scale insects, and aphids. Many are scavengers and consume various organic remains, decaying plants, seedlings, and fungi. In captivity, many species have been successfully reared on a diet of ground, commercial dry dog food, supplemented with lettuce and aphids.
According to the social historian Derek Birley, there was a "great upsurge of sport after the Restoration" in 1660. Gambling on sport became a problem significant enough for Parliament to pass the 1664 Gambling Act, limiting stakes to £100 which was, in any case, a colossal sum exceeding the annual income of 99% of the population. Along with prizefighting, horse racing and blood sports, cricket was perceived to be a gambling sport. Rich patrons made matches for high stakes, forming teams in which they engaged the first professional players. By the end of the century, cricket had developed into a major sport which was spreading throughout England and was already being taken abroad by English mariners and colonisers – the earliest reference to cricket overseas is dated 1676. A 1697 newspaper report survives of "a great cricket match" played in Sussex "for fifty guineas apiece" – this is the earliest known match that is generally considered top-class.
Cricket has close historical ties with Australian rules football and many players have competed at top levels in both sports. In 1858, prominent Australian cricketer Tom Wills called for the formation of a "foot-ball club" with "a code of laws" to keep cricketers fit during the off-season. The Melbourne Football Club was founded the following year, and Wills and three other members codified the first laws of the game. It is typically played on modified cricket fields.
Subject to certain variations, on-field clothing generally includes a collared shirt with short or long sleeves; long trousers; woolen pullover (if needed); cricket cap (for fielding) or a safety helmet; and spiked shoes or boots to increase traction. The kit is traditionally all white and this remains the case in Test and first-class cricket but, in limited overs cricket, team colours are worn instead.