Definition of whitefish
1 a
: any of various freshwater salmonid food fishes (especially of genera Coregonus and Prosopium) that resemble the salmon and trout in having an adipose dorsal fin but have a smaller, often toothless mouth and that inhabit cold lakes and streams of the northern hemisphere — see cisco
b
: any of various fishes (such as a menhaden or a whiting) resembling the true whitefishes
2
: the flesh of a whitefish especially as an article of food
