zaibatsu UK /zaɪˈbætsuː/US /zaɪˈbɑtsu/ noun2 •(US) Any large corporation. •(historical) A large business conglomerate founded under the Empire of Japan, generally controlled by a single family or individual.He wondered briefly what it would be like, working all your life for one zaibatsu. Company housing, company hymn, company funeral. — 1984 formszaibatsus