I actually found about 6 or seven diffent theories of the derivation of "Easter" - the truth of the matter is that in the 700's (1300 years ago) the term "Easter" was already in use and it's derivation had already been lost. Bede's writings conjectured that it was derived from Eostre. (which is believed in itself to have derived from a word meaning "Dawn")

For MOST of the Christian world the holiday is named using a derivation of the Hebrew for "Passover"