" 
 ::probably a majority of the RS use 1947. eg Walker, The Cold War: A History p36 (British author); Klein, Cold War Orientalism p 22; The A to Z of the Cold War (2005) p 238; Hogan, A Cross of Iron p12; but other sdates are sometimes given such as 1946= Ross Gregory, Cold War America, 1946 To 1990;  in 2nd place is the year 1946 esp Churchill's ""Iron Curtain"" speech as in Bodden, The Cold War; 1948 is a late datesee  Salmon, The Rise and Fall of Corporate America - Page 214; Russians like to use 1917-18 as the start. I don;t see any major historian using 1945 as the start (see Nargele, Endless Cold War - Page 1.   "