Billion (bn)

The number 1,000,000,000 (one thousand million). This is now generally the meaning in both British and American English. According to Oxford, in British English, a billion used to be a million million, i.e. 1,000,000,000,000, while in American English it always was a thousand million, i.e. 1,000,000,000. British English eventually adopted the American figure. (A million million is now called a trillion in both English varieties.)