Eudemonia (also spelled eudaemonia, after the Latin transliteration of the original Greek, and eudaimonia, a transliteration into English of the Greek) means "a state of happiness and well-being," or when used specifically in Aristotelian philosophy, "happiness in a life of activity governed by reason; prosperity through logic." Indeed, entire books such as Aristotle on Eudaemonia by J.L. Ackrill exist to discuss what the word means in philosophy, and fields like virtue ethics continue to use the term, though not always agreeing on exactly what it is and how it is achieved. However, no one seems to deny that in that philosophy eudemonia is the highest end for people.
Eudaimonia/Eudaemonia was also a minor figure in Greek mythology, the goddess of happiness, prosperity and opulence and a member of the retinue of Aphrodite. Like most of this retinue, she is not much discussed in surviving classical works, but is frequently pictured with Aphrodite in paintings. Eudaimonia is speculated to fit into the Greek pantheon as one of several children of Dionysus and Hera who became part of Aphrodite's group.
The word comes from the Greek for "happiness," which is derived from the roots "eu-" (good) and "daimon" (spirit, fate, or fortune). (Yes, this is the same Greek word whose "spirit" meaning was Christianized into the English "demon." Thus a eudemon, 'good demon,' is defined by Webster 1913 as a guardian angel.)
Eudemonia (in one spelling or another) has been chosen as the name of an Australian farm/vacation rental home, a German company that (from my limited scanning of their German-language web page) seems to make RiskReporter software, a British "Life and Business Coaching" firm, and a Dutch hypnotherapist/Neuro-Linguistic Programmer.
Sources:
http://www.wordsmith.org/awad/archives/1202
http://www.books.md/E/dic/eudemonia.php
http://www.textkit.com/support-textkit/
http://www.swif.uniba.it/lei/foldop/foldoc.cgi?eudaimonia
http://enlightenment.supersaturated.com/essays/text/carolynray/aristotleeudaimonia.html
http://en.wikipedia.org/wiki/Eudaimonia
http://www.eudaimonia.com/
http://www.theoi.com/Kronos/Paidia.html
http://www.theoi.com/Kronos/Kharites2.html
http://users.bigpond.net.au/sherwoodnrm/eude.htm
http://www.eudemonia.de/
http://www.eudaemonia.co.uk/
http://www.eudaimonia.nl/