Alternatively, as Hutton suggests, Eosturmonath simply meant “the month of opening,” which is comparable to the meaning of “April” in Latin. The names of both the Saxon and Latin months (which are calendrically similar) were related to spring, the season when the buds open.
So Christians in ancient Anglo-Saxon and Germanic areas called their Passover holiday what they did—doubtless colloquially at first—simply because it occurred around the time of Eosturmonath/Ostarmanoth. A contemporary analogy can be found in the way Americans sometimes refer to the December period as “the holidays” in connection with Christmas and Hanukkah, or the way people sometimes speak about something happening “around Christmas,” usually referring to the time at the turn of the year. The Christian title “Easter,” then, essentially reflects its general date in the calendar, rather than the Paschal festival having been re-named in honor of a supposed pagan deity.
Of course, the Christian commemoration of the Paschal festival rests not on the title of the celebration but on its content—namely, the remembrance of Christ’s death and resurrection. It is Christ’s conquest of sin, death, and Satan that gives us the right to wish everyone “Happy Easter!”
via Was Easter Borrowed from a Pagan Holiday? | Christian History.