Probably from an old given name *Nako (oblique *Navo-) through a form like *Navonmaa(literally “Nako's land”). The name may be related to the Estonian place name Navesti, Navaste (name of a village and river in southwestern Estonia),[1] although Estonian sources derive this instead from naba.[2]
The internal locative cases (inessive, illative and elative) are used with this place name when referring to a location; for example, "in Nauvo" is Nauvossa.
^ Sirkka Paikkala, editor (2007), Suomalainen paikannimikirja [Book of Finnish Place names] (in Finnish), Helsinki: Karttakeskus, Kotimaisten kielten tutkimuskeskus, →ISBN