The crossword solution for the term 'Jolson's Ruby' is 'Keeler, ' which is a reference to the American actress and singer Ruby Keeler. Ruby Keeler was famously married to Al Jolson, an American singer, comedian, and actor who was one of the most popular entertainers in the United States during the 1920s and 1930s. Ruby Keeler was best known for her performance in the 1933 film musical 42nd Street.