An Etymological Dictionary of the German Language/rein

by Friedrich Kluge

rein, adj. ‘pure, clean, downright,’ from the equiv. MidHG. reine, OHG. reini, older hreini, adj.; corresponding to Goth. hrains, OIc. hreinn, OSax. hrêni, North Fris. rian, ‘pure’; in Du. and E., correspondences are wanting. The ModHG. sense (for which in Bav. and Swiss sauber is mostly used) is not found in the dials.; e.g., in Rhen.-Franc. and Swiss it signifies only ‘fine ground, sifted’ (of flour, sand, &c.), and belongs therefore to the Teut. root hrī̆, pre-Teut. krī̆, krei, ‘to winnow, sift,’ whence OHG. rîtara (see Reiter), Lat. cri-brum, Gr. κρί-νειν (for the adj. suffix -ni- see klein and schön). Hence ‘sifted’ may be assumed as the orig. sense of rein; comp. OLG. hrêncurni, ‘wheat.’