And gold runs a principality (7)
I believe the answer is:
andorra
'principality' is the definition.
(I've seen this before)
'and gold runs a' is the wordplay.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'runs' becomes 'r' (cricket abbreviation).
'and'+'or'+'r'+'a'='ANDORRA'
(Other definitions for andorra that I've seen before include "Small European country" , "Territory" , "Mountainous principality of southwest Europe" , "Radar on (anag) - European principality" , "part of Europe" .)