An Etymological Dictionary of the German Language/Gras
Gras, n., ‘grass,’ from the equiv. MidHG. and OHG. gras, n.; corresponding to OSax. and Du. gras, AS. grœs (gœrs), E. grass, Goth. gras, n., ‘herb’; common to Teut. but unknown to the other Aryan languages. Allied to MidHG. gruose (Goth. *grôsa), ‘young shoot, green of plants’; probably the s in these words is a suffix, so that the Teut. root is grâ-; comp. Gr. χόρτος, ‘grass.’ An Aryan root ghra- is also attested by Lat. grâmen, as well as by ModHG. grün and its cognates.