Source : Webster's Revised Unabridged Dictionary (1913)

Ai \A"i\, n.; pl. {Ais}. [Braz. a["i], ha["i], from the animal's
   cry: cf. F. a["i].] (Zo["o]l.)
   The three-toed sloth ({Bradypus tridactylus}) of South
   America. See {Sloth}.