The machzor (Hebrew: מחזור, plural machzorim, pronounced [maχˈzoʁ] and [maχzoˈʁim], respectively) is the prayer book which is used by Jews on the High Holy Days of Rosh Hashanah and Yom Kippur.
Many Jews also make use of specialized machzorim on the three pilgrimage festivals of Passover, Shavuot, and Sukkot.
The term machzor originally referred to a book containing prayers for the entire year, including weekdays and Shabbat as well as holidays.
[3] Some of the earliest formal Jewish prayerbooks date from the tenth century; they contain a set order of daily prayers.
Many of the prayers in the machzor, including those said daily or weekly on the Sabbath, have special melodies sung only on the holidays.