The Roman Map of Britain Tueborios ? River Teifi, Cardiganshire

TouerobioV potamou ekbolai Tuerobis fluvii ostia (Ptolemy II 3 2) 

If TouerobioV is an error for ToueborioV, then the name means 'Tywi (Towy) of the north' to differentiate it from the Carmarthenshire Tywi ToisobioV p.e. Toesobis fluvii ostia (Ptolemy II 3 2) .