When writing Paradise Lost Milton’s imagination led him to suppose a place that would serve as the capital of Hell, a place that would be inhabited only by the demons and which would be the meeting place and council chambers of all the evil spirits.
He coined a name for this imaginary place and called it Pandemonium, from the Greek pan, all, and daimon, demon.
The name passed later into general use as a polite substitute for “hell,” and through the popular notion that hell is a place of great noise and wild confusion, pandemonium now denotes also any scene of great tumult and uproar.