Nothing on oil installation in the beginning (6)
I believe the answer is:
origin
'the beginning' is the definition.
(synonyms)
'nothing on oil installation in' is the wordplay.
'nothing on' becomes 'o' (I've seen this in other clues).
'oil installation' becomes 'rig' (as in an oil rig).
'o'+'rig'+'in'='ORIGIN'
(Other definitions for origin that I've seen before include "Genesis" , "Source, root" , "Crossing of axes" , "Beginning, starting point" , "Place where something begins" .)