Billion

According to the French and American method of numeration, a thousand millions, or 1,000,000,000; according to the English method, a million millions, or 1,000,000,000,000. See Numeration.

the number that is represented as a one followed by 9 zeros

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