The Collaborative International Dictionary of English v.0.48:

Crappie \Crap"pie\ (kr?p"p?), n. (Zool.)
   A kind of fresh-water bass of the genus Pomoxys, found in
   the rivers of the Southern United States and Mississippi
   valley. There are several species. [Written also croppie.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

crappie
    n 1: small sunfishes of the genus Pomoxis of central United
         States rivers
    2: small sunfishes of central United States rivers