The term 'Girl of Oz' refers to the character Sheila from the 1939 musical fantasy film The Wizard of Oz. Sheila is a young girl who is one of the main protagonists in the movie. She is a brave and loyal companion to Dorothy, and helps her on her journey to the Emerald City. Sheila is also known for her singing and dancing abilities, which she uses to help Dorothy and her friends on their quest.