1. large terrestrial monkeys having doglike muzzles
2. One of the Old World Quadrumana, of the genera Cynocephalus and Papio; the dog-faced ape. Baboons have dog- like muzzles and large canine teeth, cheek pouches, a short tail, and naked callosities on the buttocks. They are mostly African. See Mandrill, and Chacma, and Drill an ape.