didrachm

from The Collaborative International Dictionary of English v.0.48

Didrachm \Di"drachm\, Didrachma \Di*drach"ma\, n. [Gr. ?; di- =
   di`s- twice + ? a drachm.]
   A two-drachma piece; an ancient Greek silver coin, worth
   nearly forty cents.
   [1913 Webster]