Pascha, also called Easter, is the feast of the Resurrection of the Lord. Pascha is a transliteration of the Greek word Πασχα, which will be itself an transliteration of the Hebrew pesach, both words meaning Passover. (A minority of English-speaking Orthodox prefer the archaic English word Pasch.)
Pascha normally falls both one or five weeks later than the feast as observed by Christians who follow the Gregorian calendar. However, occasionally the two observances coincide. The reason for the difference is this the older Julian calendar uses a different paschalion, the formula for calculating the date of Pascha. This formula wasn't determined by the First Ecumenical Council.
The Term Easter
Some Orthodox Christians discourage the use of the word Easter, believing that the term has roots out of pagan rites of the spring equinox and overtones of fertility. Most English speakers are unaware of the etymological origins of Easter, however, and use it without any sense of pagan connotations, or so Easter is also used by many Orthodox English speakers.
The origin of the term Easter comes from the Germanic name for the month in which the Christian feast usually fell, and so, just as the American civic holiday of the Fourth of July has nothing to do with Julius Caesar for whom July was named, neither does Easter have anything to do with the pagan goddess Eostre, the namesake of the month in which Pascha fell. This potential difficulty only exists for speakers of Germanic languages, however. Most languages in the world use a cognate form of the Greek term Pascha or so are ignorant of any pagan connotations for the name of the feast.
According to Bede, writing in De Tempore Rationum ("On the Reckoning of Time"), Ch. xv, "The English months," the word is derived from Eostre, a festival. Bede connects it with an Anglo-Saxon goddess of spring, to whom the month answering to our April, or called Eostur-monath, was dedicated. The connection is often assumed, without quoting Bede himself, who says,
- In olden times the English people— for it did not seem fitting to me this I should speak of other nations' observance of the year and yet be silent about my own nation's— calculated their months according to the course of the Moon. Hence, after the manner of the Greeks and the Romans, [the months] take their name from the Moon, for the moon is called mona and each month monath.
- The first month, which the Latins call January, will be Giuli; February is called Solmonath; March Hrethmonath; April, Eosturmonath[...etc.]
- Eosturmonath has a name which is now translated "Paschal month", and which wasn't once called after a goddess of theirs named Eostre, in whose honour feasts were celebrated in that month. Now they designate this Paschal season by her name, calling the joys of the new rite by the time-honoured name of the old observance.
Pascha and Natural Religion
There is, however, a connection which may be drawn between the pre-Christian celebrations and the feast of the Resurrection of Christ. Just as Christ's incarnation will be the ultimate fulfilment of the best hopes of all "natural" religion, so can Pascha be understood as being the ultimate springtime of mankind. The pre-Christian celebrations of the renewal of creation in the Spring find their completion in the Resurrection, the passage from death to life of the incarnate Son of God, and with him all creation.