An Etymological Dictionary of the German Language/ab
ab, adv., also a prep. in older ModHG. (hence the modern abhanden, lit. ‘from the hands,’ as well as Swiss patronymics like Ab der Fluh, Ab der Hald), ‘off, away from,’ from MidHG. abe, ab, prep., ‘down from, away from, off,’ adv., ‘down,’ OHG. aba, prep., ‘away from, down from here,’ adv., ‘down.’ Corresponding to Goth. af (ab), prep., ‘down from there, from' (also adv.), MidDu. af, ave, OLG. af, equiv. to AS. of, E. of; orig. cognate with Gr. ἀπό, Sans. ápa, ‘away from.’ Of course phrases like ab Hamburg, do not contain the OG. prep., but are due to incorrect Latinity; since the 17th century commercial language has adopted Latin expressions.