Gillion

/gil'y*n/ or /jil'y*n/

[formed from Giga- by analogy with mega/million and tera/trillion] n. 10^9. Same as an American billion or a British 'milliard'. How one pronounces this depends on whether one speaks Giga- with a hard or soft 'G'.

More Jargon:

Math-Out
FredNet
Feeper