Entire band gathered round large board (6,5)
I believe the answer is:
dinner table
'board' is the definition.
(I know that dinner table is a type of board)
'entire band gathered round large' is the wordplay.
'gathered' indicates an anagram (the letters are gathered into a new order).
'round' is an insertion indicator.
'large' becomes 'L' (eg in clothes sizes).
'entire'+'band'='entireband'
'entireband' is an anagram of 'dinnertabe'.
'dinnertabe' going around 'l' is 'DINNER-TABLE'.
(Another definition for dinner table that I've seen is " Where meals are served".)