Please answer a question about the following article about Samurai:

For example, the full name of Oda Nobunaga would be "Oda Kazusanosuke Saburo Nobunaga" (織田上総介三郎信長), in which "Oda" is a clan or family name, "Kazusanosuke" is a title of vice-governor of Kazusa province, "Saburo" is a formal nickname (yobina), and "Nobunaga" is an adult name (nanori) given at genpuku, the coming of age ceremony. A man was addressed by his family name and his title, or by his yobina if he did not have a title. However, the nanori was a private name that could be used by only a very few, including the Emperor.

What did Saburo mean?
a formal nickname (yobina)