in the naval architecture of the ancients, is a word used to express such of their galleys as had three, four, five, or more tiers of rowers, located at different heights; they were distinguished by this term from the monocrota, or those which had only single rows of oars. The number of rows of rowers in the poly-crote galleys has given occasion to some to suppose those vessels of such a height from the water as is scarcely credible. Commentators are not at all agreed upon the construction of these vessels.