The "lecture circuit" is a euphemistic reference to a planned schedule of regular lectures and keynote speeches given by celebrities, often ex-politicians, for which they receive an appearance fee. In Western countries, the lecture circuit has become a way for ex-politicians to earn an income after leaving office or to raise money and their public profile in advance of a run for higher office. The Oxford Dictionary defines the term simply as, "A regular itinerary of venues or events for touring lecturers or public speakers".
In the United States, the modern lecture circuit was preceded by the Lyceum movement, popular during the 19th century. It encouraged local organisations and institutions to sponsor lectures, debates and instructional talks as a form of adult education and entertainment. The subsequent 20th century formalisation of the lecture circuit as a genuine and accepted vocation has led to the establishment of agencies and the employment of agents dedicated to identifying and filling lucrative speaking engagements; creating a specific media market where speakers are able to put their message to an audience uninterrupted and without challenge.