From The Collaborative International Dictionary of English v.0.48 [gcide]:
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]