the English name "greyhound" does not mean "gray dog/hound", but simply "fair dog". Subsequent words have been derived from the Proto-Indo-European root *g'her- 'shine, twinkle': English gray, Old High German gris 'grey, old', Old Icelandic griss 'piglet, pig', Old Icelandic gryja 'to dawn', gryjandi 'morning twilight', Old Irish grian 'sun', Old