Eudaemon, eudaimon, or eudemon in Greek mythology was a type of daemon or genius, which in turn was a kind of spirit. A eudaemon was regarded as a good spirit or angel, and the evil cacodaemon was its opposing spirit.
The word eudaemon in Greek means having a good attendant spirit, happy. It is constructed by the prefix eu, which means "well" or "good", plus the suffix daemon, which is divinity, spirit, divine power, fate, or god. Also daemon is the Greek derivative for the term demon, in which case "demon" means "replete with knowledge". Sometimes eudaemon is incorrectly taken to mean literally "good spirit".
Eudaemons in Greek mythology included deified heroes. They were regarded intermediary spirits between gods and the men. Eudaemons, the good daemons, were understood as guardian spirits, bestowing protection and guidance to ones they watched over.
As a counselor, the eudaemon whispered advice and opinions in one's ear. Such person escorted by the eudaemon was considered fortunate. It was said that Socrates during his lifetime had a daemon that always warned him of threats and bad judgment, but never directed his actions. According to Socrates, his daemon was more accurate than the respected forms of divination at that time, such as either reading the entrails or watching the flights of birds.
Other definitions 
Under philosophic views such as those by Aristotle, a happy person is one who is eudaemon, but still in a literal manner one possessing a good or fortunate daemon. And for Heraclitus, the man’s character is his guardian daemon.
Once in a while the good daemon may also stand for the souls of the deceased. For example, the heroine Alcestis in 438 BCE Athenian tragedy by the Greek Euripides, is reported as a "blessed daemon" subsequent to her death.
In mystical approaches eudaemon is sometimes defined as a symbol of "higher self", or the individual in the "causal body." As well it is a symbol of intelligence on the "buddhic plane" and higher esoteric planes, which assists evolution and is related to the higher thoughts and emotions.
See also 
- Russell, Michael; W, J. T. (1865); Vol I, p 157.
- Merriam-Webster (1995); p 392.
- Prior, William J. (1990); p 150.
- Guiley, Rosemary E. (2008); p 94.
- Wilhelm, Robert (1995); p 22.
- Smith, William (1844); p 295.
- Cooksey, Thomas L. ( 2010); pp 69-71.
- Cooksey, Thomas L. (2010). Plato's 'symposium': a reader's guide. Continuum. ISBN 0826444172.
- Merriam-Webster; Encyclopedia Britannica, ed. (1995). Merriam-Webster's Encyclopedia of Literature. Merriam-Webster. ISBN 0877790426.
- Russell, Michael; Wheeler, James T. (1865). A Connection of Sacred and Profane History from the death of Joshua to the decline of the kingdoms of Israel and Judah. London: William Tegg. OCLC 7051604.
- Prior, William J. (1990). Virtue and knowledge: an introduction to ancient Greek ethics. Routledge. ISBN 0415024706.
- Wilhelm, Robert (2002). Return to Soul: An invitation to view the soul. iUniverse. ISBN 0595221491.
- Guiley, Rosemary Ellen (2008). The Encyclopedia of Witches, Witchcraft and Wicca. Facts on File. ISBN 0816071039.
- Smith, William (1844). Dictionary of greek and roman biography and mythology. 1, Abaeus-Dysponteus. London: Taylor and Walton John Murray. OCLC 492553013.