Chris ‧ tie, Ag ‧ a ‧ tha /ˈkrɪsti, ˈæɡəθə/ BrE AmE
(1890–1976) a British writer known for her many popular novels about murders and the ↑ detective s who try to find out who did them. Her most famous characters are Miss ↑ Marple and Hercule ↑ Poirot , and two of her best-known books are Murder on the Orient Express and Death on the Nile , which have both been made into films.