What's in a Word?
Ancient Greek Concepts in Modern Language

Demon

from Greek daimon, guardian spirit

In most contemporary literature and speech, the terms daimon, daemon and demon appear - erroneously - to be synonyms; and sometimes there is not even a distinction made between demons and angels.

• Daimon
  One should be aware, however, that in ancient Greece, a daimon was most often regarded as a beneficent personal guardian spirit or guardian angel. Such a definition is a far cry from the now usual concept of a demon as an evil and/or unclean entity; the way in which both daimons and daemons are defined and described in the Bible and similar texts.
• Daemon
  In Latin, the language of the Roman empire with its many imported, adapted customs and adopted deities, the Greek beneficient daimon became a daemon; and the beings also acquired different qualities. A good or beneficent spirit was called agathodaemon (based on the Greek agathos, good, useful), yet a malefic or bad spirit was known as cacodaemon (based on the Greek kako, evil).
• Demon
  Based on the negative aspect of the Latin daemon, and aided by Christian dominance throughout almost two millennia, the term demon now always denotes an evil spirit, a force, influence or power opposed to personal and/or collective evolution and fulfilment.
  However, one should be very much aware that the demons maligned by one religious system frequently are/were the deities of another one. Like in our own times, it's usually all about spin and spin-doctors.