any of various parasitic flatworms, e.g. a liver fluke: classes Trematoda and Monogeneachiefly NAmer a flatfish, esp a flounder [Old English flōc]
the part of an anchor that digs into the sea, river, etc bottoma barbed end, e.g. of a harpooneither of the lobes of a whale's tail [perhaps from fluke1; from its flat shape]
an accidental success, and therefore one unlikely to be repeated If I foul up now, they'll all laugh and say Easy Rider was a fluke — Jack Nicholsona strange or lucky coincidence It was a fluke that we discovered the answer flukey adjfluky adj[origin unknown]