köken: Probably from Old Norse akr reenforced by Old English æcer (“a field, land, that which is sown, sown land, cultivated land; a definite quantity of land, land which a yoke of oxen could plough in a day, an acre, a certain quantity of land, strip of plough-land; crop”). Unit of measurement used only in Normandy and often attested in Norman literature and in texts from this region.