noun
or hoshanah rab·bah or hoshana rab·ba -ˈrä(ˌ)bä, -_bə
Usage: usually capitalized H&R
Etymology: Aramaic hōsha'nā rabbā
: the 7th day of the Festival of Sukkoth observed on the 21st day of Tishri with special prayers and ceremonies in the synagogue by Orthodox and Conservative Jews