Holstein UK /ˈhɒlʃtaɪn/US /ˈhoʊlstaɪn/ noun3 •A geographic region and former duchy between the rivers Elbe and Eider, to the south of Schleswig, part of the state of Schleswig-Holstein, Germany.Schleswig refuses to be separated from Holstein. — 1880 •A breed of dairy cattle, distinctively colored in splotches of black and white. •A breed of horse, thought to be the oldest of the warmblood breeds, used in show jumping. formsHolsteins · holsteins