The Collaborative International Dictionary of English v.0.48:

Johannes \Jo*han"nes\ (j[-o]*h[a^]n"n[=e]z), n. [NL., fr. Gr. ?,
   Heb. Y[e^]h[=o]kh[=a]n[=a]n, Y[=o]kh[=a]n[=a]n, i. e., one
   whom Jehovah has blessed; hence F. Jean, E. John.] (Numis.)
   A Portuguese gold coin of the value of eight dollars, named
   from the figure of King John which it bears; -- often
   contracted into joe; as, a joe, or a half joe.
   [1913 Webster]