Source : WordNet®

one million million
     n 1: the number that is represented as a one followed by 12
          zeros; "in England they call a trillion a billion" [syn:
           {trillion}, {1000000000000}]
     2: the number that is represented as a one followed by 12
        zeros; in the United Kingdom the usage followed in the
        United States is frequently seen [syn: {billion}, {1000000000000}]