Tithonus is the Latinized form of Tithonos from Greek Mythology.
This lists a possible meaning and the only one I've come across:
http://www.etymologica.com/page20.htm
~~~~~Amanda~~~~~Midnight stands darkly on the road,
and burdened by stars, tumbles down.
You can't step beyond your fence
without trampling the universe.
-"The Steppe" Boris Pasternak