Lag B’Omer is a joyful Jewish holiday that takes place in the springtime. The meaning of “Lag” is “thirty-three,” derived from gematria, a system of associating each Hebrew letter with a number. “B’Omer” means “of the Omer,” the Omer being the forty-nine day period between Passover and Shavuot. Thus, Lag B’Omer is the thirty-third day of this period.