Source : Webster's Revised Unabridged Dictionary (1913)

Panther \Pan"ther\, n. [OE. pantere, F. panth[`e]re, L.
   panthera, Gr. ?, prob. fr. Skr. pundr[=i]ka a tiger.]
   1. (Zo["o]l.) A large dark-colored variety of the leopard, by
      some zo["o]logists considered a distinct species. It is
      marked with large ringlike spots, the centers of which are
      darker than the color of the body.

   2. (Zo["o]l.) In America, the name is applied to the puma, or
      cougar, and sometimes to the jaguar.

Source : WordNet®

panther
     n 1: a large spotted feline of tropical America similar to the
          leopard; in some classifications considered a member of
          the genus Felis [syn: {jaguar}, {Panthera onca}, {Felis
          onca}]
     2: a leopard in the black color phase
     3: large American feline resembling a lion [syn: {cougar}, {puma},
         {catamount}, {mountain lion}, {painter}, {Felis concolor}]