Game bird turned up as an illustration (6)
I believe the answer is:
bridge
'an illustration' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'game bird turned up as' is the wordplay.
'game' indicates an anagram (a game or puzzle of the letters).
'turned up' says the letters should be written backwards.
'as' becomes 'eg' (both can introduce an example).
'eg' back-to-front is 'ge'.
'bird' anagrammed gives 'brid'.
'brid'+'ge'='BRIDGE'
Can you help me to learn more?
(Other definitions for bridge that I've seen before include "Game; cross (river)" , "Span, connecting structure" , "English composer" , "spanner" , "going across river?" .)