Presumably all-female cult are changing terminology (12)
I believe the answer is:
nomenclature
'terminology' is the definition.
(synonyms)
'presumably all-female cult are changing' is the wordplay.
'presumably all female' becomes 'nomen' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'changing' is an anagram indicator.
'cult'+'are'='cultare'
'cultare' is an anagram of 'clature'.
'nomen'+'clature'='NOMENCLATURE'
Can you help me to learn more?
(Other definitions for nomenclature that I've seen before include "list of names" , "System involving naming" , "Particular terminology - near Uncle Tom (anag)" , "Neater column (anag) - terminology" , "Classified system of names" .)