Few words have had their value slashed as dramatically as 'billion'. The term was coined in fifteenth-century France, most likely by the mathematician Nicolas Chuquet, who built it from bi- ('two', from Latin bis) and the tail end of million. The logic was elegant: a million to the first power is a million, a million to the second power (bi-) is a billion, a million to the third (tri-) is a trillion. Under this 'long scale', a billion equalled a million million — what we now call a trillion in English. The system worked perfectly until the seventeenth century, when an alternative 'short scale' emerged, stepping up by thousands instead of millions. American English adopted the short scale early. British English resisted for centuries, creating persistent confusion in finance and diplomacy, until the UK government formally switched in 1974. Today, most English speakers mean 10^9 when they say billion. But in Spanish, German, and most European languages, the long scale endures — their billón is still a million million.