The Sacred Triduum (sundown on Holy Thursday to Sundown on Easter Sunday) is considered the most solemn part of the liturgical year. The 3-day period is a time spent recounting the last 3 days of Jesus' life on earth, the events of his Passion and Resurrection, when the Lamb of God laid down his life in atonement for our sins.
“Though chronologically three days, they are liturgically one day unfolding for us the unity of Christ’s Paschal Mystery” (USCCB).
What Is Holy Week?
For some Christians, the week preceding Easter is known as Holy Week. It begins on Palm Sunday and is traditionally a week of somber reflection on the events preceding Jesus’ death: his triumphant entry into Jerusalem; his betrayal by Judas; his Last Supper with his twelve apostles; his arrest, crucifixion and death; and his burial in a tomb.
What Is Palm Sunday?
On Palm Sunday, Christians celebrate Jesus’ procession into Jerusalem, which occurred several days before his death. According to the gospels, the people of Jerusalem spread branches from trees—identified specifically as palm branches in John's gospel—on the road to welcome Jesus as he rode a donkey into the city. Because of this, many Christian churches today offer congregants palm fronds as they enter the church on Palm Sunday. In some denominations, the story of Jesus’ entry into Jerusalem and of his death is read in church on Palm Sunday, juxtaposing the welcome Jesus received on one day with his betrayal and arrest a few days later.
What Is Holy Thursday?
On Holy Thursday (also called Maundy Thursday), Christians commemorate the Last Supper—a Passover meal that Jesus shared with his disciples the night before his death. During the meal, Jesus broke bread and offered his followers wine, saying “This is my body, given up for you.” Many Christians consider this event to have been the institution of the Eucharist, which is a sacrament in some denominations.
What Is the Passion?
Though today the word “passion” has romantic connotations, it was originally derived from the Latin word passio, meaning suffering. In religious contexts, the Passion (often capitalized) refers to the torture, crucifixion, and death of Jesus.
What Is a Passion Play?
A Passion play is a reenactment of the gospel stories of Jesus’ trial, torture by Roman soldiers, and crucifixion, often with a focus on the carrying of the cross. During Holy Week, Christian groups may stage performances of Passion plays in churches or processions through streets; actors from the congregation play the roles of various characters in the gospels. While many Christians today find Passion plays moving, some interfaith experts consider Passion plays problematic because they have incited anti-Semitic violence in the past by blaming Jews for Jesus' death.
What Is Good Friday?
Christians observe Good Friday (for English-speaking Eastern Orthodox Christians, “Great and Holy Friday”) as the day Jesus was crucified and died. It is the most somber day on the Christian calendar. On Good Friday, some Christians abstain from meat or refrain from food altogether. They may also attend special church services that might include readings from the gospel stories of Jesus' Passion, Jesus' last words, and other Bible passages. Catholics often make the Stations of the Cross on Good Friday.
What Is the Triduum?
For Catholics and some other Christians, the Triduum is the three-day period marking Jesus' death and burial. It begins on Holy Thursday and concludes as Easter begins. Some Christians observe the Triduum by attending a worship service on each day, including a long Easter Vigil service on the night before Easter.
What Is Pascha?
Pascha is the Greek word for the Jewish feast of Passover. With the coming of Christianity, Pascha became the Greek and Latin word for Easter. Eastern Orthodox Christians today still use the word Pascha in referring to Easter, even in English-speaking countries.
What Is Easter?
Easter is the most important Christian holiday, surpassing even Christmas. As a celebration of the day Jesus rose from the dead, Easter symbolizes forgiveness, rebirth, and God’s saving power. Christians view the day as a victory over sin, death, and all destructive forces in people’s lives.
Source: beliefnet.com