Fluke (flūk), n. [Cf. LG. flunk, flunka wing, the palm of an anchor; perh. akin to E. fly.] 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. A. Trollope.