There are various potential roots behind the name Porto (as for example, 'door' or 'gate', 'harbour' or 'port'). It could also mean 'carriage' or 'bearing', from which we derive the modern word 'portly', which might seem to be a suitable origin for a Hobbit-name. In context, however, it seems doubtful that the name was intended to carry a modern meaning. Porto Baggins came from a long line of Hobbits dating back to his great-grandfather Ponto who all had names fitting the pattern 'Po...o' (Ponto, Polo, Posco and another Ponto, who was Porto's elder brother) and it seems that Porto's name simply continued this trend among his branch of the Baggins family.