Social divisions as sect is formed (6)
I believe the answer is:
castes
'social divisions' is the definition.
(I've seen this in another clue)
'as sect is formed' is the wordplay.
'is formed' indicates anagramming the letters.
'as'+'sect'='assect'
'assect' is an anagram of 'CASTES'.
(Other definitions for castes that I've seen before include "Hindu social divisions or classes" , "Social divisions in India" , "Hereditary social classes among Hindus" .)