A large edible marine flatfish (Pleuronectes platessa) of western European waters.
Any of various flatfishes, such as Hippoglossoides platessoides of North American Atlantic waters, related to the plaice.
[Middle English, from Old French plais, from Vulgar Latin *platīx, alteration of Late Latin platessa, probably ultimately from Greek platus, broad; see plat- in Indo-European roots.]