Romeo for example, on the wagon, seen in AA meeting (7)
I believe the answer is:
regatta
'meeting' is the definition.
(I've seen this before)
'romeo for example on the wagon seen in aa' is the wordplay.
'romeo' becomes 'r' (phonetic alphabet: alpha, bravo, charlie etc.).
'for example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'on the wagon' becomes 'tt' (short for teetotal).
'seen in' indicates putting letters inside.
'tt' inserted within 'aa' is 'atta'.
'r'+'eg'+'atta'='REGATTA'
(Other definitions for regatta that I've seen before include "event held on water" , "competition between banks" , "Rowing, sailing, gala" , "event at the seaside" , "Craft meeting" .)