The closing rounds (4,6)
I believe the answer is:
last orders
'the' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'closing rounds' is the wordplay.
'closing' becomes 'last' (similar in meaning).
'rounds' becomes 'orders' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'last'+'orders'='LAST ORDERS'
Can you help me to learn more?
(Another definition for last orders that I've seen is " mine host may call for them".)