The term 'Gaslight and Big Band' refers to the era of music from the 1930s to the 1950s. This era was characterized by the emergence of big band swing music, as well as the development of jazz and blues. The term 'Gaslight and Big Band' is derived from the popular musical revue 'Gaslight and Big Band', which was produced in the late 1940s. This revue featured a variety of musical styles, including swing, jazz, and blues. The era of Gaslight and Big Band music was an important part of American culture during this time period, and its influence can still be heard today.