What is a "mother hubbard"?

Mother Hubbard is a loose-fitting, long dress typically made of cotton, with a high neck and long sleeves that are gathered at the wrist. It has a very simple design and is usually gathered at the waist with a belt or ribbon. The dress was originally worn by Quaker women in the 19th century as a practical and modest everyday garment. Today, the Mother Hubbard has evolved into a popular nightgown or loungewear, with many variations in fabric and style.