fluke Meaning, Definition & Usage

  1. noun a stroke of luck
    good luck; good fortune.
  2. noun a barb on a harpoon or arrow
  3. noun flat bladelike projection on the arm of an anchor
    flue.
  4. noun either of the two lobes of the tail of a cetacean
  5. noun parasitic flatworms having external suckers for attaching to a host
    trematode; trematode worm.

WordNet

Fluke noun
Etymology
Cf. LG. flunk, flunka wing, the palm of an anchor; perh. akin to E. fly.
Definitions
  1. The part of an anchor which fastens in the ground; a flook. See Anchor.
  2. (Zoöl.) One of the lobes of a whale's tail, so called from the resemblance to the fluke of an anchor.
  3. An instrument for cleaning out a hole drilled in stone for blasting.
  4. An accidental and favorable stroke at billiards (called a scratch in the United States); hence, any accidental or unexpected advantage; as, he won by a fluke. Cant, Eng. A. Trollope.

Webster 1913