What does Hoshannah Rabbah mean?
Translates as "The Great Hoshannah". This refers to the fact that on this day there are more Hoshanot said than all the previous days of the festival.
What are Hoshanot though
They are special prayers that are said as the congregation walks around the synagogue whilst holding their Lulav and Etrog. This procession is lead by the chazan.
The congregation marches around the bimah seven times, after which comes the beating of the Aravah, willow branch. The Aravot are beaten against the floor five times. No blessing is recited.
What are the customs of Hoshannah Rabbah?
On this day, the white curtain on the ark, in synagogue, remains up until after Hoshannah Rabbah.
Oct. 10th - 11th
12th Tishri
Begins: 18:04
Ends: 19:03
Sedra: Haazinu