Bluefin

from WordNet (r) 3.0 (2006)

bluefin
    n 1: flesh of very large tuna [syn: {bluefin}, {bluefin tuna}]
    2: largest tuna; to 1500 pounds; of mostly temperate seas: feed
       in polar regions but breed in tropics [syn: {bluefin},
       {bluefin tuna}, {horse mackerel}, {Thunnus thynnus}]

from The Collaborative International Dictionary of English v.0.48

Bluefin \Blue"fin`\, n. (Zool.)
   A species of whitefish ({Coregonus nigripinnis}) found in
   Lake Michigan.
   [1913 Webster]