Easter-observing Christians commonly refer to the week before Easter as Holy Week, which in Western Christianity begins on Palm Sunday (marking the entrance of Jesus in Jerusalem).
Good Friday commemorates the crucifixion and death of Jesus.
In Eastern Christianity, the same events are commemorated with the names of days all starting with “Holy” or “Holy and Great”, and Easter itself might be called “Great and Holy Pascha”.
In Western Christianity, Eastertide, or the Easter Season, begins on Easter Sunday and lasts seven weeks, ending with the coming of the 50th day, Pentecost Sunday.
In Eastern Christianity, the Paschal season ends with Pentecost as well, but the leave-taking of the Great Feast of Pascha is on the 39th day, the day before the Feast of the Ascension.