greyhoundyoudaoicibaDictYouDict[greyhound 词源字典]
greyhound: [OE] Most greyhounds are not grey – and there is no etymological reason why they should be. For the element grey- in their name has no connection with the colour-term grey. It comes from an unrecorded Old English *grīeg ‘bitch’, a relative of Old Norse grøy ‘bitch’.
[greyhound etymology, greyhound origin, 英语词源]
greyhound (n.)youdaoicibaDictYouDict
Old English grighund (West Saxon), greghund (Anglian) "greyhound," probably from grig- "bitch," a word of unknown etymology, + hund "dog" (see hound (n.)). The first element in the name apparently has nothing to do with color, as most of the hounds are not gray, but the exact sense of it must have been early forgotten, as it has been long associated with the color in popular imagination. In some Middle English forms it appears to be conformed to Grew, an old word for "Greek" (from Old French Griu). The Old Norse form of the word is preserved in Hjalti's couplet that almost sparked war between pagans and Christians in early Iceland:
Vilkat goð geyja
grey þykkjumk Freyja

I will not blaspheme the gods,
but I think Freyja is a bitch