noun: 1. A resin secreted by the lac insect and purified for use in varnishes, paints, inks, sealing waxes, phonograph records, etc. 2. A phonograph record, especially a 78 rpm. 3. A severe defeat or beating. verb tr.: 1. To coat or treat with shellac. 2. To thrash soundly. 3. To defeat decisively, especially in a contest or game.