The Collaborative International Dictionary of English v.0.48:

Cavally \Ca*val"ly\, n. [Cf. Pg. cavalla a kind of fish; Sp.
   caballa; prob. fr. Pg. cavallo horse, Sp. caballa.] (Zool.)
   A carangoid fish of the Atlantic coast (Caranx hippos): --
   called also horse crevall['e].

   Note: [See Illust. under Carangoid.]
         [1913 Webster]

WordNet (r) 3.0 (2006):

Caranx hippos
    n 1: fish of western Atlantic and Gulf of Mexico [syn: crevalle
         jack, jack crevalle, Caranx hippos]