In american english Billion and Trillion means something different than in british english

While this "fact" is often repeated, it's worth noting that this has not been true for several decades: Britain has used the same system as the United States for more than a generation, and it's the same in Australia and New Zealand.

For example Wikipedia states that common use of the "short scale" in the UK grew steadily for "several decades" prior to 1974 when the government finally made it official. So, throughout the majority of the 20th century the public has used the same scale as the United States.

http://en.wikipedia.org/wiki/Long_and_short_scales

As others have said though, outside of the English-speaking world the long scale is often still used in Europe.

You might want to crosspost to /r/linguistics or /r/asklinguistics for an answer from someone who studies historical linguistics.

Follow up: I feel like this is something I could and probably should research myself, but what's the origin of the word million? In Latin, mille is 1000, so it's always puzzled me how million is three orders of magnitude bigger than mille.