The Oxford Thesaurus An A-Z Dictionary of Synonyms - holocaust n.

1) conflagration, fire-storm, inferno, fire; destruction, devastation: When the volcano exploded, few escaped the holocaust. 2) genocide, mass murder, massacre, blood bath, pogrom, butchery, carnage, annihilation, extinction, extermination, eradication, elimination: Survivors of the Nazi holocaust hold periodic memorial services.