1) Coin of ancient Greece 
The tetradrachm (τετράδραχμον) was an Ancient Greek silver coin equivalent to four drachmae. In Athens it replaced the earlier `heraldic` type of didrachms and it was in wide circulation from ca. 510 to ca. 38 BC. ==History== The transition from didrachms to tetradrachms occurred during ca. 525-510 BC; the abandonment of the `herald......
• (n.) Alt. of Tetradrachma
An ancient Greek silver coin weighing about 13 to 17 grams, similar in size to a U.S. quarter but much thicker.
A four-drachma coin of Ancient Greece. This was made of Silver (Ag).
Tet'ra·drachm Tet`ra*drach'ma noun [ New Latin tetradrachma , from Greek tetra`drachmon ; te`tra- (see Tetra- ) + drachmh` drachm, drachma.] A silver coin among the ancient Greeks, of the value of four drachms. The Attic tetradrachm