Mid 17th century: modern Latin (denoting the place of all demons, in Milton's Paradise Lost), from pan- 'all' + Greek daimōn 'demon'.
For book 1 of his epic poem Paradise Lost, published in 1667, John Miltoninvented Pandemonium – from the Greek pan (all), and daimon (evil spirit), literally "a place for all the demons" – or, as Milton first expressed in the poem: "A solemn Councel forthwith to be held At Pandæmonium, the high Capital Of Satan and his Peers." Later in the work he calls it the "citie and proud seat of Lucifer". By the end of the century, Pandemonium had become a synonym not just for hell, but, because the devils created a lot of noise, uproar and tumult. In 1828, Edward Bulwer-Lytton applied it to a common location: "We found ourselves in that dreary pandaemonium … a Gin-shop." Today, the term is applied to any scene of disarray, confusion or even heightened activity as in the headline: iPad pandemonium.