An Etymological Dictionary of the German Language/Granne
Granne, f., ‘bristle (of swine), awn,’ from MidHG. gran, grane, f., ‘point of hair, moustache, fish-bone’ (in the latter sense Granne is also used dial.), OHG. grana, ‘moustache’; corresponding to AS. grǫnu, OIc. grǫn, ‘moustache.’ To the Goth grana, recorded by Isidore, are due Span. greña, ‘tousled hair,’ and OFr. grenon, ‘moustache and whiskers.’ The Teut. cognates are primit. allied to OIr. grend, Gael. greann, ‘moustache’ and ‘shaggy hair.’ See Grat.