In which, the ballerina repeats a half turn (4)
I believe the answer is:
tutu
'in which the ballerina' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'repeats a half turn' is the wordplay.
'repeats' shows that letters should be duplicated.
'a half' indicates taking half.
'turn' cut in half is 'tu'.
'tu' duplicated is 'TUTU'.
Can you help me to learn more?
(Other definitions for tutu that I've seen before include "Archbishop Desmond" , "Ballerina's stiff skirt" , "Ballet-dancer's skirt" , "outfit" , "Short dress" .)