Apophanypes

Epiphany (Greek: επιφάνεια, "the appearance; miraculous phenomenon") is a Christian feast intended to celebrate the 'shining forth' or revelation of God to mankind in human form, in the person of Jesus. http://en.wikipedia.org/wiki/Epiphany

Apocalypse the greek name of the last book of the bible, also known as "Revelations". Also means the end of the world, because "Revelations" describes the end of the world, and is the last book of the bible.

So this word, referring to Epiphany and Apocalypse, combines endings and beginnings, refers to this being the last chapter of Finnigans Wake and the fresh start, which is what happens in the song "Finnegan's Wake" because Finnegan wakes up again.