Examine gold divided into three crowns (5)
I believe the answer is:
audit
'examine' is the definition.
(an audit is an examination)
'gold divided into three crowns' is the wordplay.
'gold' becomes 'Au' (Au is the chemical symbol for gold).
'crowns' suggests taking the first letters (the letters at the top).
The first letters of 'divided into three' is 'dit'.
'au'+'dit'='AUDIT'
(Other definitions for audit that I've seen before include "special ale" , "Formally examine" , "vetting of books" , "Financial review" , "Roman Aquae Sulis" .)