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 machzor is a specialized form of the siddur, which is generally intended for use in weekday and Shabbat services.