Crude oil in a USA state (9)
I believe the answer is:
louisiana
'state' is the definition.
(Louisiana is an example)
'crude oil in a usa' is the wordplay.
'crude' is an anagram indicator.
'oil'+'in'+'a'+'usa'='oilinausa'
'oilinausa' anagrammed gives 'LOUISIANA'.
(Other definitions for louisiana that I've seen before include "State named for French king" , "Southern United State on the Gulf of Mexico" , "that's near Mississippi" , "IOU a snail over in the US state" , "American state, capital Baton Rouge" .)