An Etymological Dictionary of the German Language/Annotated/fach

by Friedrich Kluge

fach, adjective, suffix, ‘-fold,’ from Middle High German (very rare) vach, in manecvach, zwivach, Old High German not found; mannigfach, literally ‘with many divisions’; moreover, Middle High German vach, denotes also ‘fold,’ and -fach as a suffix may be an imitation of the earlier suffix -falt in manecvalt, ‘manifold.’