Billion
1,000,000,000, i.e. one thousand million, or 109 (ten to the ninth power), as defined on the short scale. This is now the meaning in both British and American English. 1,000,000,000,000, i.e. one million million, or 1012 (ten to the twelfth power), as defined on the long scale. This is one thousand times larger than the short scale billion, and equivalent to the short scale trillion. This is the historic definition of a billion in British English. American English adopted the short scale definition from the French. The United Kingdom used the long scale billion until 1974, when the government officially switched to the short scale, but since the 1950s the short scale had already been increasingly used in technical writing and journalism; the long scale definition still enjoys some limited usage in the UK.
Billion-2