Real tripod occasionally providing balance (5)
I believe the answer is:
ratio
'balance' is the definition.
(thesaurus)
'real tripod occasionally' is the wordplay.
'occasionally' means one should take alternating letters (letters taken at regular intervals or occasions).
'real'+'tripod'='realtripod'
The alternating letters of 'realtripod' are 'RATIO'.
'providing' acts as a link.
(Other definitions for ratio that I've seen before include "Comparative figure" , "2:1, for example" , "Relationship of numbers" , "Relationship between two amounts" , "Comparative measure" .)