Holy Week (Latin: Hebdomas Sancta or Hebdomas Maior, "Greater Week"; Greek: Ἁγία καὶ Μεγάλη Ἑβδομάς, Hagia kai Megale Hebdomas) 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), Good Friday, and Holy Saturday. It does not include Easter Sunday. In Eastern Orthodox tradition, Holy Week starts on Lazarus Saturday, the day before Palm Sunday. (Easter Sunday, for context, is the first day of the new season of the Great Fifty Days, or Eastertide, there being fifty days from Easter Sunday to Pentecost Sunday.)

Holy Week in the Christian year is the week immediately before Easter. The earliest Catholic allusion to the custom of marking this week as a whole with special observances is to be found in the Apostolical Constitutions (v. 18, 19), dating from the latter half of the 3rd century and 4th century. In this text, abstinence from flesh is commanded for all the days, while for the Friday and Sunday an absolute fast is commanded. Dionysius Alexandrinus in his canonical epistle (AD 260), refers to the 91 fasting days implying that the observance of them had already become an established usage in his time.^[1]