An Etymological Dictionary of the German Language/Lambertsnuß
Lambertsnuß, f., ‘filbert,’ instinctively connected by Germans with St. Lambert, but the historic term is lombardische Nuß, ‘Lombard nut’; MidHG. Lambardîe, Lombardîe, and Lámpart,’ ‘Lombardy, Italy.’ Comp. Walnuß.