Easter

Easter (Greek: Πάσχα, Pascha) is the most important religious feast in the Christian liturgical year. Christians believe that Jesus was resurrected from the dead three days after his crucifixion. Many Christian denominations celebrate this resurrection on Easter Day or Easter Sunday (also Resurrection Day or Resurrection Sunday), two days after Good Friday. The chronology of his death and resurrection is variously estimated between the years 26 and 36 A.D.

Holy Week

The entry of Jesus into Jerusalem on Palm Sunday marks the beginning of Holy Week.
For the 1958 novel of the same name by Louis Aragon, see La Semaine Sainte.
Holy Week (Latin: Hebdomada Sancta or Maior Hebdomada, "Greater Week") in Christianity is the last week of Lent and the week before Easter. It includes the religious holidays of Palm Sunday, Maundy Thursday (Holy Thursday) and Good Friday, and lasts from Palm Sunday (or in the Eastern, Lazarus Saturday) until but not including Easter Sunday, as Easter Sunday is the first day of the new season of The Great Fifty Days. It commemorates the last week of the earthly life of Jesus Christ culminating in his crucifixion on Good Friday and his resurrection on Easter Sunday.

Holy Week in the Western Church
Monday to Wednesday
The days between Palm Sunday and Maundy Thursday are known as Holy Monday (or Fig Monday), Holy Tuesday and Holy Wednesday (sometimes called Spy Wednesday). The Gospels of these days recount events not all of which occurred on the corresponding days between Jesus' entry into Jerusalem and his Last Supper. For instance, the Monday Gospel tells of the Anointing of Bethany which occurred before the Palm Sunday event described in John 12:12-19.
The Chrism Mass, whose texts the Roman Missal now gives under Holy Thursday, may be brought forward to one of these days, to facilitate participation by as many as possible of the clergy of the diocese together with the bishop. This Mass was not included in editions of the Roman Missal before the time of Pope Pius XII. In this Mass the bishop blesses separate oils for the sick (used in Anointing of the Sick) for catechumens (used in Baptism) and chrism (used in Baptism, but especially in Confirmation and Holy Orders, as well as in rites such as the blessing of an altar and a church).
Holy Week in Eastern Christianity
In Eastern Orthodox Churches and Eastern Catholic Churches, Holy Week is referred to as "Great and Holy Week". Orthros (Matins) services for each day are held on the preceding evening. Thus, the Matins service of Great Monday is sung on Palm Sunday evening, and so on. This permits more of the faithful to attend, and shows that during Holy Week the times are out of joint—Matins ends up being served in the evening, and in some places Vespers is served in the morning.
Fasting during Great and Holy Week is very strict. Dairy products and meat products are strictly forbidden. On most days, no alcoholic beverages are permitted and no oil is used in the cooking. Friday and Saturday are observed as strict fast days, meaning that nothing should be eaten on those days. However, fasting is always adjusted to the needs of the individual, and those who are very young, ill or elderly are not expected to fast as strictly. Those who are able to, may receive the blessing of their spiritual father to observe an even stricter fast, whereby they eat only two meals that week: one on Wednesday night and one after Divine Liturgy on Thursday.
The services of Sunday through Tuesday evenings are often called "Bridegroom Prayer", because of their theme of Christ as the Bridegroom of the Church, a theme expressed in the troparion that is solemnly chanted during them. On these days, an icon of the "Bridegroom" is placed on an analogion in the center of the temple, portraying Jesus wearing the purple robe of mockery and crowned with a crown of thorns (see Instruments of the Passion).

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