State of patio was observed (4)
I believe the answer is:
iowa
'state' is the definition.
(I know that Iowa is a state)
'of patio was observed' is the wordplay.
'of' indicates the answer is hidden within the clue.
'IOWA' is hidden within 'patio was observed'.
(Other definitions for iowa that I've seen before include "'Hawkeye State'" , "US state, three vowels" , "State of USA" , "part of United States" , "Midwest US state" .)