‘Yannopoulos’ or 'Giannopoulos' is a Greek surname (pronounced 'Ya-No-Pu-Los') from Giannis, vernacular form of Iōannēs ‘John’ + the patronymic ending -poulos. This ending occurs chiefly in the Peloponnese; it is derived from Latin pullus (‘nestling’, ‘chick’). Also see: Genealogical Tree