`atserah "assembly" usually a religious "assembly"
(Am 5:21), seems at times
a technical term for the last day of a festival season (especially the feast of booths/tabernacles: Lev 23:36;
Num 29:35; Neh 8:18;
2 Chron 7:9),
in Joel it suggests a day of fasting and prayer in the context of Adonai's Day
(Joel 1:14; 2:15).