Detail from Death and the Miser, a painting by Hieronymus Bosch, in the National Gallery of Art, Washington, D.C.

A demon or daemon is a supernatural bad, powerful or malevolent being in many world religions. The word 'demon' has different meanings all over the world, but often there is the idea that they are spirits that lived in a place, or went with a person. The word is also used for a type of computer program that does useful things in the background of a computer, but this use is not related to the religious meaning.