Flatfish

Any fish of the family Pleuronectidae; 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.

any of several families of fishes having flattened bodies that swim along the sea floor on one side of the body with both eyes on the upper side