An Etymological Dictionary of the German Language/mehr
mehr, adj. and adv., ‘more,’ from MidHG. mêr; compar. of viel; also, doubly compared, mêrer, mē̆rre, ‘greater or larger’ (of space, number, and value); further indeclin. mêre, mêr, mê, ‘plus’; OHG. mêr, undeclin. neu. and compar. adv., ‘more, plus, magis, amplius,’ adj. mêro, ‘major, greater’ (also with the addition of the compar. suffix mêrôro, mêriro, ‘major’). OHG. mêro originated in maizo, Goth. maiza, the -iza- of which is the OTeut. compar. suffix (comp. besser, Goth. batiza; höher, Goth. hauhiza); comp. AS. mâ, adv. and neu. subst., ‘more,’ adj. mâra, E. more. The corresponding superl. is meist. Goth. maiza, for *majiza, belongs, with the Goth. superl. maists (see meist), to the Teut. adj. mê-rs, ‘projecting,’ discussed under Märchen.