Several decades ago, a 'billion' in British English was a 'million million'; i.e. 10^12. In the USA, however, it was [only] a thousand million; 10^9. Since then the British version has gradually lost the battle [initially in Canada and Australia, but now even in the UK] - such that few if any people stick to the old interpretation. However, what A says is true - there is still confusion when it is heard in continental Europe; i.e., in Spanish "un billón" is indeed 10^12 - but because science is dominated by the English language, Spaniards always find it necessary to emphasise that they really do mean 10^12. The same is true when speaking French, German and Italian; in these latter countries too it is 10^12 ... Thus, the Kwiziq 'large numbers' site does need to be modified to reflect this fact.

[^Has now been done;Thank you Inma !]