An Etymological Dictionary of the German Language/Fach
Fach, n., ‘compartment, shelf, panel, special branch,’ from MidHG. vach, OHG. fah(hh), n., ‘part, division of space, of a partition, wall, &c.,’ also ‘contrivance, an enclosed space in water for catching fish, fish-weir, hurdles for fishing’; with the latter meanings some have connected Gr. πάγη, ‘noose, snare, fishing hurdles,’ to which there is no objection phonetically. Yet we must proceed in the case of the HG. word as well as of AS. fœc, ‘space, time,’ from a general and primary sense, such as ‘division, a portion of space or time.’ Allied to HG. fügen. —