From Longman Dictionary of Contemporary EnglishLondon Season, thethe London SeasonˌLondon ˈSeason, the (also the Season) a series of social events held every year in or near London and attended by people from the highest social class. In the past, this was an important part of life for the British upper class, but it is much less important now. It includes parties for debutantes, and several well-known sports events, including Royal Ascot and the Henley Regatta.
