What Hebrew phrase meaning 'Sabbath of Sabbaths' describes Yom Kippur?

Shabbat Shabbaton is the Hebrew phrase describing Yom Kippur as a “Sabbath of Sabbaths.”

The expression appears in the Torah's regulations for the holy day and is often translated more idiomatically as “a Sabbath of solemn rest” or “a Sabbath of complete rest.” Its repeated-sounding form emphasizes that Yom Kippur is an exceptionally sacred day on which ordinary work is prohibited.

Yom Kippur shares the Sabbath's work restrictions, but it adds distinctive practices connected with atonement, including fasting, extended prayer, confession, and abstention from several physical comforts. The phrase therefore highlights rest and holiness, not simply a weekly day off.

Readers sometimes confuse Shabbat Shabbaton with names of other special Sabbaths. Shabbat Shuvah is the Sabbath between Rosh Hashanah and Yom Kippur; Shabbat HaGadol precedes Passover; and Shabbat Chazon comes before Tisha B'Av.