Additional small traditions (5)

I believe the answer is:

'traditions' is the definition.
(I've seen this in another clue)

'additional small' is the wordplay.
'additional' becomes 'more' (synonyms).
'small' becomes 's' (abbreviation - e.g. clothes size).
'more'+'s'='MORES'

(Other definitions for mores that I've seen before include "codes" , "Conventional values" , "Way of life" , "Fundamental values of a group" , "Customs and conventions of a community" .)

I've seen this clue in The Mirror.

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