Dawn. It means dawn.
It comes, via a few steps, from the Proto-Germanic *austron-, meaning dawn, and also used as the name of a a goddess of fertility and the spring. The link between the spring and the dawn is clear enough: the beginning of life and activity after a period of darkness and inactivity.
Naturally enough, the rites of this goddess were celebrated at the beginning of spring, and as is often the case with religious festivals, Anglo-Saxon Christians chose to celebrate the resurrection of Jesus at this time due to the thematic similarities.
The word Easter is actually quite different from the equivalent in other European languages. Most use a variation of the Latin Pascha, which can be traced back to the Aramaic pasha (pass over), referencing of course the Old Testament tale of God passing over the houses of Jewish families when he killed the first-born sons of the Egyptians, which is still celebrated as the Jewish holiday Passover.
We can still find traces of this in the English language in the name Pasc(h)al, and the fact that pascal is the adjective used to refer to Easter and Passover, though it’s not something you’re likely to need to use every day.