Tree-lined street, a meeting-place (6)
I believe the answer is:
avenue
'tree-lined street' is the definition.
(I've seen this before)
'a meeting-place' is the wordplay.
'meeting-place' becomes 'venue' (I've seen this before).
'a'+'venue'='AVENUE'
(Other definitions for avenue that I've seen before include "A wide street or access route" , "Wide street or road as in New York" , "Road leading to a house" , "suburban street" , "Double row of trees" .)