popolo noun2 •black nightshade (Solanum nigrum).Popolo is a branching green herb with a tendency to being woody at the base. This annual grows one to three feet high on cultivated land and is regarded as a common weed. — 1975 •(slang) A black person.Well, I'm a Hawaiian, but my father was a black-assed popolo—a Portuguese from Bravas, Cabo Verde Islands, who changed his name. — 2004 formspopolos