Chaos was the archaic term for the Otherness (see "Demonsong"). As time went on and people came to realize that chaos is the quotidian state of reality, the terminology evolved. (How's that for fudging off the top of my head?)
FPW
FAQ
"It means 'Ask the next question.' Ask the next question, and the one that follows that, and the one that follows that. It's the symbol of everything humanity has ever created." Theodore Sturgeon.