An Etymological Dictionary of the German Language/grün
Appearance
grün, adj., ‘green, fresh, vigorous, unripe,’ from MidHG. grüene, OHG. gruoni, ‘green, fresh’; corresponding to OSax. grôni, Du. groen, AS. grêne, E. green, OIc. grœ́nn, Goth. *grô-ni-, ‘green'; allied to a Teut. root grô, ‘to grow, become green.’ Comp. MidHG. grüejen, OHG. gruoan, ‘to grow green’; AS. grôwan, E. to grow, Du. groeijen, ‘to grow, thrive.’ Akin to Gras and its Aryan cognates.