An Etymological Dictionary of the German Language/zahm
zahm, adj., ‘tame, tractable, docile,’ from the equiv. MidHG. and OHG. zam; corresponding to Du. tam, AS. tǫm, ‘E. tame, and OIc. tamr, ‘tame, domesticated.’ Allied to zähmen, vb., ‘to tame, domesticate, break in, check,’ from MidHG. zęmen (zęmmen), OHG. zęmmen (from *zamjan), wk. vb., ‘to tame’; corresponding to Goth. gatamjan, OIc. temja, Du. temmen, ‘to tame.’ The connection between the Teut. cognates and Lat. domare, Gr. δαμᾶν, Sans. damáy (damany), ‘to subdue, compel,’ is undoubted. The relation of these cognates based on dom, ‘to subdue,’ to a similar root appearing in ModHG. ziemen (Teut. root tem, ‘to be suitable, be fitted’) is obscure. OHG. zęmmen, ‘to tame,’ looks as if it were a causative of OHG. zëman, ‘to be adapted, suit excellently.’ In that case it is remarkable that the primary verb has been preserved in Teut. only; but was it perhaps deduced from the causative? (see wecken).