The crossword solution for the term 'Bygone Theaters' is RKOS, which stands for 'RKO Studios'. RKO Studios was an American film production and distribution company that operated from 1928 to 1959. It was founded by the merger of two smaller companies, Radio Pictures and Keith-Albee-Orpheum, and was known for producing classic films such as King Kong, Citizen Kane, and The Hunchback of Notre Dame.