What is the day before Rosh Hashanah commonly called?

The day before Rosh Hashanah is commonly called Erev Rosh Hashanah.

“Erev” is Hebrew for “eve,” so the phrase literally means “Rosh Hashanah eve.” It refers to the final day of the Hebrew month of Elul, before the holiday begins at sundown. Because Jewish calendar days begin in the evening, preparations and observances often start before the first official day of Rosh Hashanah.

The day is traditionally associated with spiritual preparation. Some communities recite selichot, penitential prayers, while others perform hatarat nedarim, a ceremony for annulling certain vows. Many observant Jews also visit a mikveh before the holiday. These customs reflect Rosh Hashanah’s themes of repentance, judgment, and renewal.

Erev Rosh Hashanah is not the same as Yom Kippur Katan, a minor-day observance practiced in some communities, or Shabbat Shuvah, the Sabbath between Rosh Hashanah and Yom Kippur. Rosh Hashanah itself begins on 1 Tishrei and traditionally continues for two days in many Jewish communities.