Flatfish \Flat"fish`\, n. (Zool.)
Any fish of the family {Pleuronectid[ae]}; esp., the winter
flounder ({Pleuronectes Americanus}). The flatfishes have the
body flattened, swim on the side, and have eyes on one side,
as the flounder, turbot, and halibut. See {Flounder}.
[1913 Webster] flat foot