Billions

noun

1. (modern British & Australian, short scale) a thousand million (logic: 1,000 × 1,000^2): 1 followed by nine zeros, 109; a milliard
2. (British & Australian, long scale) A million million (logic: 1,000,000^2): a 1 followed by twelve zeros; 1012
3. An unspecified very large number.

   "There were billions of people at the concert."