Aylesbury (ālzˈbərē) [key], city (1991 pop. 51,999), Buckinghamshire, central England. It is an agricultural market for the upper Thames valley and is famous for its ducks. There are printing works, food processing, engineering, and other light industries, developed under a government program undertaken to disperse London's population and industry to surrounding counties. The radical John Wilkes represented Aylesbury in Parliament during the late 18th cent.