Understanding, go round to have a meal (6)
I believe the answer is:
treaty
'understanding' is the definition.
(treaty is a kind of understanding)
'go round to have a meal' is the wordplay.
'go' becomes 'try' (I've seen this before).
'round' is an insertion indicator.
'to have a meal' becomes 'eat' (I've seen this before).
'try' going around 'eat' is 'TREATY'.
(Other definitions for treaty that I've seen before include "'Pact, accord (6)'" , "Pact or agreement between nations" , "Compact; concordat" , "Contract, pact" , "Ratified agreement between states" .)