n. A purified lac in the form of thin yellow or orange flakes, often bleached white and widely used in varnishes, paints, inks, sealants, and formerly in phonograph records.n. A thin varnish made by dissolving this substance in denatured alcohol, used to finish wood.n. An old phonograph record containing this substance, typically played at 78 rpm.v. To coat or finish with shellac.v. Slang To strike repeatedly and severely; batter.v. Slang To defeat decisively.