Origin of the Word Easter
Just as there are many traditions surrounding the celebration of Easter, there are many stories and legends surrounding the origin of the word Easter. To some, it is the history and celebration of spring; for others it is a day to remember deliverance; for many it is the celebration of new life in Christ. Let's look at a few explanations:
Eostre - a pagan Anglo-Saxon Goddess
This mythical figure is said to have been the goddess of the sunrise and the spring. She is the Teutonic goddess of the dawn. The direction of the sunrise, East, is named for her. In Norse mythology, the name is spelled Eostare. Another considered the Norse/Saxon goddess of spring is Ostara. Eastre is believed to be an ancient word for spring.
Pesach - the Passover

While pagans celebrated the rites of spring, the Jews celebrated Passover, the anniversary of the day God delivered them out of Egyptian bondage. God had demanded the firstborn male from every household, but had promised to pass over any house with the blood of a perfect lamb smeared on its doorpost. He then commanded the Jews to remember their deliverance through the ceremony of the Passover. Pesach is the Hebrew word for Passover. Its position in the Jewish calendar coincidentally corresponds to the beginning of Spring.
Easter: An Early Celebration of Christ's Resurrection
Another idea involves the history of the Frankish church (Germans who settled in Rome during the fifth century). Their the celebration of Christ's resurrection included the word alba, which means white (the color of the robes worn during the resurrection festival). Alba also meant sunrise. So when the name of the festival was translated into German, the sunrise meaning, ostern, was selected, likely in error. One theory is that Ostern is the origin of the word Easter.

Throughout Scripture, God speaks of the Sacrificial Lamb. Beginning in Genesis 22; we read of God's command to Abraham that he sacrifice his son Isaac, the son of God's promise. When Abraham obediently raises his hand to sacrifice Isaac, God stops him. He is satisfied that Abraham is a man of great faith. When Isaac asks his father "where is the lamb for the sacrifice?", Abraham replies, "God will provide Himself the sacrifice." Many believe this was the first foreshadowing of the time when God Himself would become the sacrifice for all the sin of man, through the person of Jesus Christ.

Christians believe the deeper meaning of the Passover involves this sacrifice, as Jesus himself was crucified on the Friday of Passover week and resurrected on Passover Sunday. Because He is seen as the ultimate Sacrificial Lamb, anyone who accepts the gift of His sacrifice is said to have His blood on the doorposts of their hearts. Therefore, when the final judgment comes, God will pass them over. In Christ, those who believe are set free from the power and penalty of sin.

Origin of the Word Easter: What does it mean today?
More important than the question of how the word Easter originated is what it means to us today. When you

think of the word Easter, what do you see? If you see bunnies and baskets of chocolate eggs, you are missing out on the richness of this day, considered by many Christians to be even more significant than Christmas. Easter, to Christians, is actually Resurrection Day - the anniversary of the day Jesus rose in triumph from the grave, claiming victory over death. Because He lives, so can you and I, through simple faith in Him. God provided Himself the sacrifice. Thanks to Him, you and I have the hope of eternal life with Him. Won't you trust in Him today?

 Encyclopedias - International Standard Bible Encyclopedia - Easter

EASTER

es'-ter (pascha, from Aramaic paccha' and Hebrew pecach, the Passover festival):

The English word comes from the Anglo-Saxon Eastre or Estera, a Teutonic goddess to whom sacrifice was offered in April, so the name was transferred to the paschal feast.

The word does not properly occur in Scripture, although the King James Version has it in Acts 12:4 where it stands for Passover, as it is rightly rendered in the Revised Version (British and American). There is no trace of Easter celebration in the New Testament, though some would see an intimation of it in 1 Corinthians 5:7. The Jewish Christians in the early church continued to celebrate the Passover, regarding Christ as the true paschal lamb, and this naturally passed over into a commemoration of the death and resurrection of our Lord, or an Easter feast.

This was preceded by a fast, which was considered by one party as ending at the hour of the crucifixion, i.e. at 3 o'clock on Friday, by another as continuing until the hour of the resurrection before dawn on Easter morning. Differences arose as to the time of the Easter celebration, the Jewish Christians naturally fixing it at the time of the Passover feast which was regulated by the paschal moon. According to this reckoning it began on the evening of the 14th day of the moon of the month of Nissan without regard to the day of the week, while the Gentile/Christians identified it with the first day of the week, i.e. the Sunday of the resurrection, irrespective of the day of the month.

This latter practice finally prevailed in the church, and those who followed the other reckoning were stigmatized as heretics. But differences arose as to the proper Sunday for the Easter celebration which led to long and bitter controversies. The Council of Nice, 325 AD, decreed that it should be on Sunday, but did not fix the particular Sunday. It was left to the bishop of Alexandria to determine, since that city was regarded as the authority in astronomical matters and he was to communicate the result of his determination to the other bishops.

But this was not satisfactory, especially to the western churches, and a definite rule for the determination of Easter was needed. By some it was kept as early as March 21, and by others as late as April 25, and others followed dates between.

The rule was finally adopted, in the 7th century, to celebrate Easter on the Sunday following the 14th day of the calendar moon which comes on, or after, the vernal equinox which was fixed for March 21. This is not always the astronomical moon, but near enough for practical purposes, and is determined without astronomical calculation by certain intricate rules adopted by ecclesiastical authority.

These rules involve the Dominical Letters, or the first seven of the alphabet, representing the days of the week, A standing for the first day of the year and the one on which Sunday falls being called the Dominical for that year. There are also involved the Golden Numbers and the Epacts, the first being the numbers from 1 to 19, the cycle of the moon when its phases recur on the same days of the year, the first of the cycle being that in which the new moon falls on January 1.

The Epacts indicate the moon's age at the beginning of each year. Easter was thus fixed by these rules, but another difficulty arose when the Gregorian calendar was adopted in 1582, the difference between it and the Julian being then 10 days. This of course affected the determination of Easter, and its celebration by the Greek church, which has never admitted the Gregorian calendar, occurs usually at a different time from that followed by the western churches. This difference may be as much as five weeks and it may occur as late as April 30, while in the West it cannot occur later than April 25 nor earlier than March 22. Occasionally the two come together but this is rare, since the difference between the two calendars is now 13 days.

The Easter feast has been and still is regarded as the greatest in the Christian church, since it commemorates the most important event in the life of its Founder.