Column containing single officer (7)
I believe the answer is:
colonel
'officer' is the definition.
(colonel is a kind of officer)
'column containing single' is the wordplay.
'column' becomes 'col'.
'containing' is an insertion indicator.
'single' becomes 'lone' ('lone' can be a synonym of 'single').
'col' going around 'lone' is 'COLONEL'.
(Other definitions for colonel that I've seen before include "Commander" , "No cello (anag.)" , "Bogey perhaps" , "Rank (below brigadier)" , "High-ranking officer" .)