Lag BaOmer is the thirty-third day of the counting of the Omer, the seven-week period between Passover and Shavuot; its name is simply the number, lag (33) ba-omer. The weeks of the Omer are kept in many communities as a period of semi-mourning, in which weddings, haircuts and music are avoided, traditionally in memory of a plague said to have killed the students of Rabbi Akiva; Lag BaOmer is the day the deaths are said to have ceased, and so it becomes a day of release, on which weddings and celebrations resume.
It is associated above all with Rabbi Shimon bar Yochai, the second-century sage to whom the mystical tradition attributes the Zohar, and whom tradition says died on this day, asking that it be marked with joy. His reputed tomb at Meron in the Galilee draws a huge annual pilgrimage, with bonfires, singing and the first haircuts of small boys; bonfires are lit across Israel and in Jewish communities elsewhere, and children play with bows and arrows, variously explained. The 2021 disaster at Meron, in which a crush killed dozens, led to a state inquiry and to tighter regulation of the pilgrimage, part of the day's recent history.