- either of two large flatfishes, Hippoglossus hippoglossus, of the North Atlantic, or H. stenolepis, of the North Pacific, used for food.
- any of various other similar flatfishes.
- the largest flatfish: a dark green North Atlantic species, Hippoglossus hippoglossus, that is a very important food fish: family Pleuronectidae
- any of several similar and related flatfishes, such as Reinhardtius hippoglossoides (Greenland halibut)
