Albacore

from WordNet (r) 3.0 (2006)

albacore
    n 1: relatively small tuna with choice white flesh; major source
         of canned tuna
    2: large pelagic tuna the source of most canned tuna; reaches 93
       pounds and has long pectoral fins; found worldwide in
       tropical and temperate waters [syn: {albacore}, {long-fin
       tunny}, {Thunnus alalunga}]

from The Collaborative International Dictionary of English v.0.48

Albacore \Al"ba*core\, n. (Zool.)
   A name applied to several large fishes of the Mackerel family
   ({Scombridae}), esp. {Thunnus alalunga} (formerly {Orcynus
   alalonga}); it is a type of tuna or tunny. The name has been
   also applied to a larger related species, {Thunnus thynnus}
   (formerly {Orcynus thynnus}), common in the Mediterranean and
   Atlantic, which is called in New England the {horse
   mackerel}. [formerly spelled {albicore}.]
   [1913 Webster +PJC]