billion

billion [Lat: ‘two’] Symbol bn. Often used to mean a huge number, but specifically defined traditionally as:North America = 1 000 million = (1 000)² thousand, = 10^(3×2)+3 = 10⁹.
UK = 1 000 000 million = (million)², = 10^6×2 = 10¹².
The index value 2 following the bracket in each is the respective etymological factor. The billion is clearly ambiguous and confusing in the intercontinental context, so should be avoided. However, the escalation of so many countable entities, from money to humans, makes such large terms of growing appropriateness. The increasingly pervasive use of the American form (despite the 9th CGPM in 1948 recommending the extant British/European formNature 163, 427–8 (1949)
) has displaced the traditional British form even in the UK. With this trend, the term has surviving value; however, such terms are yielding in either sense to expressions formed from the prefixes of the SI system (e.g. ‘megabucks’), that for 10⁹ being giga (G-). Use of billion in a scientific context is undesirable. See thousand for general discussion.