/gil' y*n/ or /jil' y*n/ (From giga- by analogy with mega/mILLion and tera/trILLion) 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". [Jargon File] (1995-03-17)