Octave
The eight-day period beginning on a major feast.
An octave is the eight-day period beginning on a major Christian feast, during which the feast continues to be liturgically celebrated. The Octave of Easter extends through the Sunday after Easter (Divine Mercy Sunday in Catholic practice); the Octave of Christmas extends from December 25 through January 1 (the Feast of Mary, Mother of God). Catholic practice still observes octaves for these two highest solemnities; older practice included octaves for many more feasts but the post-Vatican II reform reduced the list. The concept reflects the principle that the greatest feasts of the Christian year are too significant for a single day; the celebration extends across the week that follows.