The Collaborative International Dictionary of English v.0.48:

Bay \Bay\ (b[=a]), a. [F. bai, fr. L. badius brown,
   chestnut-colored; -- used only of horses.]
   Reddish brown; of the color of a chestnut; -- applied to the
   color of horses.
   [1913 Webster]

   Bay cat (Zool.), a wild cat of Africa and the East Indies
      (Felis aurata).

   Bay lynx (Zool.), the common American lynx (Lynx lynx,
      formerly Felis rufa or Lynx rufa).
      [1913 Webster]