Symbol at the centre of the Canadian national flag (5,4)
I believe the answer is:
maple leaf
'symbol' is the definition.
(I know that maple-leaf is a type of allegory)
'at the centre of the canadian national flag' is the wordplay.
'at' says to put letters next to each other.
'the centre of the canadian national' becomes 'maple' (I can't justify this - if you can you should believe this answer much more).
'flag' becomes 'leaf' (I've seen this before).
'maple' next to 'leaf' is 'MAPLE-LEAF'.
Can you help me to learn more?
(Other definitions for maple leaf that I've seen before include "Canada's eternal one?" , "Emblem of Canada" , "Canadian emblem" , "part from tree" , "national emblem" .)