GNU Collaborative International Dictionary of English

Found one definition

1.       
   ‖Yen (?), n. The unit of value and account in Japan. The yen is equal to 100 sen. From Japan's adoption of the gold standard, in 1897, to about 1913 the value of the yen was about 50 cents. In 1997 and 1998 the value of the yen varied from 80 per U. S. dollar to 120 per dollar.
   
   [1913 Webster +PJC]