A number whose value varies with geography: for example, in the U.S., it is a thousand million (1,000,000,000); in the U.K., it is a million million (1,000,000,000,000).

I believe in the UK a "billion" means a million millions (e.g. 10^12 rather than 10^9)

America and most other non-british-colonized countries (let's not debate about that): 1,000,000,000
: 1 thousand Million

Australia, The Uk etc. : 1,000,000,000,000
: 1 Million Million

How many people Lex Luthor is going to kill.

Most everywhere: One thousand millions;
1,000,000,000

Also meant to exaggerate.

In English speaking countries means 10^9, in all other languages and countries except Brazilian Portuguese means 10^12. This is because English speaking nations use the short scale, where new notation is used when multiplied by 1000, rather than the long scale where its when multiplied by a million.

A derisive term for computer geeks who proffer 3 fundamental beliefs:
1) Microsoft can do no wrong and is right and admirable to pursue dominance by any means necessary.
2) There are NO other viable computing/development platforms.
3) That successful marketing by Microsoft has not influenced their computing/technology choices.

The term "Billion" is a combination of 'Bill' (Bill Gates, Microsoft co-founder and it's most recognizable face) and 'Legion'. So, "billion" = "Bill's Legions." Also, it's a play on the idea that such people eagerly add billions of dollars to Mr. Gates' fortunes.