(lɑg ˈboʊ mər, bəˈoʊ mɛr) n. a Jewish festival celebrated on the 33rd day of the Omer and commemorating the end of the plague among Rabbi Akiba's students. [1900–05; < Hebrew lagh bā‘ōmer=lagh 33rd + bā, variant of bə in + ‘ōmer Omer]ThesaurusSeeLag b'Omer