Ashoura is a period of intense grief and mourning. The word ashura simply means tenth in Arabic language, the 10th day of Muharram in the Islamic calendar.
It is commemorated by Shia Muslims as a day of mourning for the martyrdom of Husayn ibn Ali, the grandson of the Islamic Prophet Muhammad at the Battle of Karbala on 10 Muharram in the year 61 AH (October 2, 680 CE).