Separation (7)
'separation' is the definition.
(splitting something into parts)
This is all the clue.
(Other definitions for parting that I've seen before include "splitting up" , "Leaving or dividing" , "Separating" , "Aggressive remarks on leaving (from a 20?)" , "Separation" .)
'separation' is the definition.
(divorce is a kind of separation)
This is the entire clue.
(Other definitions for divorce that I've seen before include "Split" , "Get separated" , "Part" , "Ending of marriage" , "Break-up" .)