The Jardim do Largo da Maternidade Júlio Dinis, which translates to the 'garden of the maternity square of Júlio Dinis'. The square and garden part are quite obvious, but who was Júlio Dinis?
Dinis was the pseudonym of Joaquim Guilherme Gomes Coelho a doctor and novelist from Porto. Born in 1839 he went on to become deputy professor of Porto's medical school only to be struck down by tuberculosis. He then turned to writing and wrote a few very popular books, the most famous of which were based on his experiences growing up with an English mother in Portugal. Sadly within a few years the TB killed Dinis at the young age of 31.
In the square is a fountain and on it the date 1840. This tells us that the square predates Dinis as he was a baby when it was built. The other part of the name refers to the maternity hospital, which is located right on the edge of the square. Then again this is named after Julio Dinis too.
Anyway, it's a very pleasant little square with some nice looking cafes around it.