An Etymological Dictionary of the German Language/Annotated/Pacht
Pacht, feminine, ‘compact, lease, tenure,’ from Middle High German (Middle German) paht, with the strictly permutated and more usual forms phaht, phahte (Middle High German), feminine and masculine, ‘rent, lease, justice, law’; so too Dutch pacht. The Modern High German form is due to Low German influence, as is indicated by the initial sound compared with Middle High German phahte. It is based on Middle Latin pactum, pactus, ‘compact, a sum stipulated by the compact.’ Old High German *pfahta is not recorded, probably only by chance, though Old High German (also Middle High German) pfât occurs a few times.