baboon

English baboon comes from Middle English babewin or baboin, from Old French babouin, from baboue meaning 'grimace' or 'muzzle', itself of imitative origin.

The word traces back to an imitative base *bab-, echoing the reduplicated syllable 'ba' of early infant babble and the lip movements of speech — a sound rooted in faces and mouths long before it settled on this particular grimacing animal.

The same imitative root *bab- lies behind English babble, babe, and baby — all words born from the instinctive 'ba' sounds of infants.