Historically, these sighthounds were used primarily for hunting in the open where their keen eyesight is valuable. It is believed that they (or at least similarly named dogs) were introduced to the area now known as the United Kingdom in the 5th and 6th century BCE from Celtic mainland Europe although the Picts and other peoples of the northern area now known as Scotland were believed to have had large hounds similar to that of the deerhound before the 6th century BCE.
The name "Greyhound" is generally believed to come from the Old English grighund. "Hund" is the antecedent of the modern "hound", but the meaning of "grig" is undetermined, other than in reference to dogs in Old English and Old Norse. Its origin does not appear to have any common root with the modern word "grey" for color, and indeed the Greyhound is seen with a wide variety of coat colors. The lighter colors, patch-like markings and white appeared in the breed that was once ordinarily grey in color. The Greyhound is the only dog mentioned by name in the Bible; many versions, including the King James version, name the Greyhound as one of the "four things stately" in the Proverbs.However, some newer biblical translations, including The New International Version, have changed this to strutting rooster, which appears to be an alternative translation of the Hebrew term mothen zarzir. But also the Douay–Rheims Bible translation from the late 4th-century Latin Vulgate into English translates "a cock girded about the loins" rather than the Greyhound.
According to Pokorny the English name "Greyhound" does not mean "grey dog/hound", but simply "fair dog". Subsequent words have been derived from the Proto-Indo-European root *g'her- "shine, twinkle": English grey, Old High German gris "grey, old", Old Icelandic griss "piglet, pig", Old Icelandic gryja "to dawn", gryjandi "morning twilight", Old Irish grian "sun", Old Church Slavonic zorja "morning twilight, brightness". The common sense of these words is "to shine; bright".
In 1928, the very first winner of Best in Show at Crufts was Primeley Sceptre, a Greyhound owned by H. Whitley.
Until the early twentieth century, Greyhounds were principally bred and trained for hunting and coursing. During the 1920s, modern Greyhound racing was introduced into the United States and England (Belle Vue Stadium, Manchester, July 1926), as well as Northern Ireland (Celtic Park (Belfast), April 1927) and the Republic of Ireland (Shelbourne Park, Dublin). Aside from professional racing, many Greyhounds enjoy success on the amateur race track. Organizations like the Large Gazehound Racing Association (LGRA) and the National Oval Track Racing Association (NOTRA) provide opportunities for Greyhounds and other sighthound breeds to compete in amateur racing events all over the United States.
Data refer : http://en.wikipedia.org/wiki/Greyhound