The pagan goddess Oestra, the goddess of fertility,

Short answer: it probably comes from the old Germanic word for the month of April: Estor-monath, which means "the month of opening(s)" Long answer: First, we need to make it clear that "Easter" is only it's name in English (and "Osterfest" in German). But most of the Christian world calls it by some adaptation of its Greek name, "PASCHA," which actually means "Passover". I hope I don't need to explain why that is or what that means. Pascha was celebrated by Christians of the Roman and Parthian Empires, as well as Armenia and Ethiopia, under this name hundreds of years before the Angles, Saxons, and Jutes became Christians. The second question is whether the English name of the holiday "Easter" comes from the blurring of the Christian celebration of Pascha with the worship of a purported Germanic pagan fertility goddess named "Eostre". The SOLE source for this belief is a single comment by the Venerable Bede in his history of the kings of England. There are several problems with this passage however. In his book, The Stations of the Sun, Professor Ronald Hutton (a well-known historian of British paganism and occultism) critiques Bede's sketchy knowledge of other pagan festivals, and argues that the same is true for the statement about Eostre: "It falls into a category of interpretations which Bede admitted to be his own, rather than generally agreed or proven fact." This leads us to the next problem: there is NO EVIDENCE outside of Bede for the existence of this Anglo-Saxon goddess. There is no equivalent goddess in the Norse Eddas or in ancient Germanic paganism from continental Europe. Hutton suggests, therefore, that "the Anglo-Saxon Estor-monath simply meant 'the month of opening' or 'the month of beginnings,'" and concludes that there is no evidence for a pre-Christian festival in the British Isles in March or April. There is another objection to the claim that Eosturmonath has anything to do with a pagan goddess. Whereas Anglo-Saxon days were usually named after gods, such as Wednesday ("Woden's day"), the names of their months were either calendrical, such as Giuli, meaning "wheel," referring to the turn of the year; metereological-environmental, such as Solmónath (roughly February), meaning "Mud-Month"; or referred to actions taken in that period, such as Blótmónath (roughly November), meaning "Blood Month," when animals were slaughtered. No other month was dedicated to a deity, with the exception (according to Bede) of Hrethmonath (roughly March), which he claims was named after the goddess Hrethe. But like Eostre, there is no other evidence for Hrethe, nor any equivalent in Germanic/Norse mythology. Another problem with Bede's explanation concerns the Saxons in continental Europe. Einhard (c. 775-840), the courtier and biographer of Charlemagne, tells us that among Charlemagne's reforms was the renaming of the months. April was renamed Ostarmanoth. Charlemagne spoke a Germanic dialect, as did the Anglo-Saxons in Britain, although their vernacular was distinct. But why would Charlemagne change the old Roman title for the spring month to Ostarmanoth? Charlemagne was the scourge of Germanic paganism. He attacked the pagan Saxons and felled their great pillar Irminsul (after their god Irmin) in 772. He tried (unsuccessfully) to forcibly convert them to Christianity and savagely repressed them when they revolted because of this. It seems very unlikely, therefore, that Charlemagne would name a month after a Germanic goddess. So why, then, do English-speaking Christians call their holiday "Easter"? One theory for the origin of the name is that the Latin phrase in albis ("in white"), which Christians used in reference to Easter week, found its way into Old High German as eostarum, or "dawn." There is some evidence of early Germanic borrowing of Latin despite that fact that the Germanic peoples lived outside the Roman Empire—though the Angles, Saxons, and Jutes were very far removed from it. This theory presumes that the word only became current after the introduction of either Roman influence or the Christian faith, which is uncertain. But if accurate, it would demonstrate that the festival is not named after a pagan goddess. 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!"