Agatha Christie's title (4)
I believe the answer is:
dame
'agatha christie's title' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for dame that I've seen before include "Titled lady" , "Pantomime role played by a man" , "Pantomime female" , "Crossdressed panto role" , "Pantomime lady" .)