1857, title given by foreigners to the shogun of Japan (said to have been used by his supporters when addressing foreigners, as an attempt to convey that the shogun was more important than the emperor), from Japanese taikun "great lord or prince," from Chinese tai "great" + kiun "lord." Transferred meaning "important person" is attested from 1861, in reference to U.S. president Abraham Lincoln (in the diary of his secretary, John Hay); specific application to "wealthy and powerful businessman" is post-World War I.