The name of this Jewish holiday means “thirty-three omer,” an omer being a sheaf of barley or wheat. In the biblical book of Leviticus, the people were commanded by Jehovah to make an offering of a sheaf of barley on each of the 50 days between Passover and Shavuot. After the evening service, the number of the day was solemnly announced, and, in time, this ceremony came to be known as “the counting of the omer.” Lag ba-Omer represents a break in the otherwise solemn season between Passover and Shavuot. Discuss
Source: The Free Dictionary